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A Bell & Howell Information Company 300 North Zeeto Road Ann Arbor. Ml 46106-1346 USA 313/761-4700 800 521-0600 CHAPTER I: SYNTHESIS AND CHEMISTRY OF 1-

(BENZENESULFONYL)-2-(TRIMETHYLSILYL)

CHAPTER II: 1,1-(DILITHIO)-1-(BENZENESULFONYL)-2-

(TRIMETHYLSILYL) AS AN EFFECTIVE SYNTHETIC

EQUIVALENT FOR SYMMETRICAL 1,1-DISUBSTITUTED TERMINAL

OLEFINS

DISSERTATION

Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University

By

Larry Yet, M.S.

The Ohio State University 1995

Dissertation Committee: Approved by:

Dr. Harold Shechter

Dr. David J. Hart

Dr. Gideon Fraenkel Advisor

Department of Chemistry □MI Number: 9534096

UMI Microfora 9534096 Copyright 1995, by UMI Coapany. All rights reserved.

This aicrofora edition is protected against unauthorized copying under Title 17, United States Code.

UMI 300 North Zeeb Road Ann Arbor, MI 48103 To My Family and Friends ACKNOWLEDGMENTS

I would like to express my sincere gratitude to Professor Harold Shechter for his complete support during the entire course of my graduate studies. His "hands off" approach to research has led me to become an independent researcher, and his outstanding classroom teaching technique has been truly inspirational.

Special thanks also go to past and present members of the Shechter group who made life pleasant both in and outside the laboratory. Drs. Mark McGuiness, Naresh Mathur, and Michael

Wheeler are gratefully acknowledged for their initial cooperative and intense attention given to me when I was first starting out. Thanks also are given to Sau Kee (Andy) Wong, Tony Skufca, Chris

Woltermann, Kirby Kendall, and Nyenty Arrey for the friendship which sustained me through my last part of graduate school.

Special mention is given to Dr. Venkat Krishnamurthy, Dr. Ron Graham and Mrs. Linda

Graham for the moral support as friends who were always available during the many ups and downs over the years. Without them, life would have been a serious struggle.

Finally, the Chemistry Department at The Ohio State University is gratefully acknowledged for their financial support and for the opportunity to teach at an outstanding research institution.

ill VITA

December 18, 1964 ...... Bom - Vancouver, British Columbia, Canada

1987 ...... B.Sc., The University of British Columbia, Van­ couver, British Columbia, Canada

1987-1993 ...... Teaching Assistant. The Ohio State University, Columbus, Ohio

1990 ...... M.S., The Ohio State University, Columbus, Ohio

m D OF STUDY

Major Field: Chemistry Studies in Organic Chemistry

iv TABLE OF CONTENTS

DEDICATION...... ii

ACKNOWLEDGEMENTS...... iii

VITA...... iv

LIST OF SCHEMES...... vii

LIST OF TABLES...... x

LIST OF FIGURES...... xi

CHAPTER PAGE

I SYNTHESIS AND CHEMISTRY OF 1 -(BENZENESULFONYL)-2-

(TRIMETHYLSILYL)CYCLOPROPANE

Statement of Problem...... 1

Introduction ...... 2

Results and Discussion...... 24

Summary of Results and Further Possible Investigation...... 67

Experimental Section ...... 68

II 1,1 -{DILITHIO)-1 -(BENZENESULFONYL)-2-(TRIMETHYLSILYL)ETHANE

AS AN EFFECTIVE SYNTHETIC EQUIVALENT FOR SYMMETRICAL

1.1-DISUBSTITUTED TERMINAL OLEFINS

Statement of Problem...... 108

v Introduction ...... 109

Previous Background...... 116

Results and Discussion ...... 117

Summary ...... 124

Experimental Section ...... 124

LIST OF REFERENCES...... 140

vt LIST OF SCHEMES

Page

1 Synthetic Utility of 1-(Benzenesulfonyl)-2-(1rimethysilyl)ethane (1) ...... 1 2 Proposed Research...... 2 3 Synthetic Utility of 1-(Benzenesulfonyl)-2-(trimethysilyl)ethane (1) ...... 3 4 1-(Benzenesulfonyl)-4-(trimethylsilyl)-2- (14) as a 1-(1,3-Butadienyl) Anion (18) Synthon ...... 4 5 1-(Benzenesulfonyl)-4-(trimethylsilyl)-2-butenes (14) as al,l-(1,3-Butadienyl) Dianion (22) Synthon ...... 5 6 o-[(Trimethylsilyl)methyl]benzyl p-Tolyl Sulfone (23) as an o-Quinodi- (26) Equivalent...... 6 7 Protodesilylation of 24 ...... 6 B Potential Syntheses of 1-(Substituted) (10) ...... 7 9 Trapping of 1,2*Dibromocyclopropene (32) with Furan ...... 8 10 Trapping of 1,2-Dibromocyclopropene (32) with Exocyclic ...... 8 1 1 Trapping of 1-Bromocyclopropene (44) with Furan and DPIBF ...... 9 12 Synthesis of 1 H-Cyclopropa[b] (53) ...... 10 13 Synthesis and Trapping of Spiropentadiene (58) with Furan...... 11 14 Synthesis of l-(Triphenylsilyl) (65) ...... 12 15 Synthesis and Trapping of H-cyclopropa[/] phenanthrene (83) with Furan 15 16 Synthesis of Benzenesulfonylcyclopropane (88) ...... 16 17 Synthesis of Cyclopropyl Sulfones 93 ...... 16 18 Synthesis of Cyclopropyl Sulfones 98 ...... 18 19 Synthesis of Cyclopropyl Sulfones 101 ...... 18 20 Synthesis of Cyclopropyl Sulfones 106 ...... 20 21 Synthesis of Cyclopropyl Sulfones 108 ...... 21

v ii 22 Synthesis of Cyclopropyl Sulfones 124 ...... 23 23 Synthesis of 2-Methylene-1-cyclopropyl Sulfones 126 ...... 23 24 Retrosynthetic Syntheses of 8 ...... 25 25 Synthesis of (E)-1-(Phenylthio)-2-(trimethylsityl)ethene (127) and (E)-1-(Benzenesulfonyl)-2-(trimethylsilyl)ethene (1 2 8 ) ...... 26 26 Preparation of (Z)-1-(p-Toluenesulfonyl)-2-(trimethylsilyl)ethene (138) ...... 27 27 Preparation of p-Toluenesulfonyldiazomethane (141).and Reaction of 141 with Trimethyl(vinyl)silane (133) to Give 1-p-(Toluenesulfonyl)- 2-(trimethylsilyl)cyctopropane (143) ...... 29 28 Attempted Anionic Cyclizations of 146 to 147 ...... 30 29 Peterson Eliminations of 145...... 30 30 Synthesis of (E)- and (Z)-1-(Benzenesulfonyl)-2-(trimethylsily!) (8) ...... 32 31 Reaction of 152 with Sodium Amalgam...... 34 32 Reaction of 8 with Fluoride Ion in the Presence of DPIBF ...... 34 33 Protodesilylation of 8 ...... 35 34 Transformations of 8 to 9 to10 ...... 36 35 Protodesilylation of 162 ...... 40 36 Reactions of 1-(Benzenesulfony!)-2-(trimethylsilyl)-2-butenes (14) with to Give 176 and Eliminations of 176 to 177...... 41 37 Reactions of 8 with Epoxides to Give 178 and Reactions of 178 with Fluoride Ion...... 42 38 Reactions of 8 with and to Give 183 and Possible Eliminations of 183 to 184 ...... 44 39 Eliminations of Sulfonyl 185 to Allylic Alcohols 186 ...... 44 40 Reactions of 1-(Benzenesulfonyl)-2-(trimethylsilyl)-2-butenes (14) with Acid Chlorides to Give 198 and Eliminations of 198 to 199 ...... 47 41 Preparation of 1 -(Acyl)-1 -(benzenesulfony1)-2-(trimethylsilyl)- cyclopropanes (200) and Reactions of 200 with Fluoride Ion ...... 48 42 Reactions of 9 with Fluoride Ions to 10 or 211 ...... 51 43 Reactions of 212 to Give Cyclopropenes 213 ...... 51 44 Attempted Eliminations of 151 and 152 to Cyclopropane 214 ...... 52

v iii 45 Fluoride Ion Reaction of 152...... 53 46 Trapping of 1,2-Dihalocyclopropenes 219 with Oienes 220 ...... 54 47 Reaction of 222 and TBAF in the Presence of 2,2-Dimethyl- 1,3-...... 55 48 Reaction of 222 and TBAF in the Presence of Furan ...... 55 49 Reaction of 1,2-Dibromocyclopropene (32) with Furan ...... 56 50 Reaction of 222 and TBAF in the Presence of Sodium Methoxide...... 57 51 Preparation of 2-Methoxy-3,3-dimethyl--1-(p-toluenesulfonyl) cyclopropane (227) ...... 57 52 Synthesis of 1 -(Styryl)cyclopropane 235 and Possible Elimination to 1 -(Styryl)vinylcyclopropene (236) ...... 61 53 E1cb Mechanism for Formation of Cyclopropene 10 ...... 63 54 E2 Mechanism for Formation of Cyclopropene 214 ...... 63 55 Reactions of Cyclopropanes 165 and 232 with TBAF Treated with n-BuLi to Give Cyclopropanes 173 and 237 ...... 64 56 Synthetic Utility of 1,1 -(Dilithio)-I -(benzenesulfonyl)-2-(trimethylsilyt) ethane (243)...... 108 57 Reactions of Allyl Anion 254/255 ...... 111 58 Generation and Reactions of Dilithio Anion 263 ...... 112 59 Use of Allyl Dilithio 253 in the Syntheses of Carbaprostacyclins 277 ...... 114 60 Methyl Jasmonates 282/283 Syntheses with Dilithio Sulfones 279 ...... 115 61 Synthetic Utility of 1-(Benzenesulfonyl)-2-(trimethyisilyl)ethane (1) ...... 116 62 Preparation of 1-(Benzenesulfonyl)-2-(trimethylsilyl)ethane (1) ...... 118

ix LIST OF TABLES

Table Page

1 Reactions of 99 to Give 100 and 100 to Give 101 ...... 19 2 Displacement Reactions of 160 with Atkyl Halides ...... 38 3 Fluoride Ion Reactions of 162 to Give A!kyt(sulfony)cyclopropanes ...... 40 4 Reactions of 8 with Epoxides to Give Cyclopropanols 178 ...... 43 5 Reactions of 8 with Aldehydes and to Give Cyclopropanols 183 ...... 45 6 Fluoride Reactions of 178 and 183 to Give Cyclopropanols 190 and 191 ...... 46 7 Reactions of 8/nBuLI with Acid Chlorides to Give Acyl Derivatives 200 ...... 49 8 Fluoride Ion Reactions of 204 to Give Acyl Products 206 ...... 50 9. Dialkylation of 1 with Halides ...... 123 10. Fluoride Ion Eliminations of Disubstituted Sulfones 244...... 124

x LIST OF FIGURES

Figure Page

1 1H NMR of the Upfield Region of (Z)-1,2-Bis(phenylthio)cyclopropane (150)...33 2 1H NMR of the Upfield Region of (Z)-1,2-Bis(benzenesulfonyl)- cyclopropane (151) ...... 33 3 1H NMR of the Upfield Region of (E)-1,2-Bis(benzenesulfonyl)- cyclopropane (217) ...... 53 4 1H NMR (200 MHz) Data for Exo 224...... 56 5 1H NMR of (E)-2-Methoxy-1-(benzenesulfonyl)cyclopropane (225) and (E)- and (Z)-2-Methoxy-3,3-dimethyl-1 -(p-toluenesulfonyt)cycloproanes (227) ...... 58 6 1H NMR (200 MHz) of 1,1 -(Dilithio)-I -(benzenesulfonyl)-2-(trimethylsilyl)ethane (243)...... 120 7 1 NMR (200 MHz) of 1,1 -(Dilithio)-I -(benzenesulfonyl)-2-(trimethylsilyl)ethane (243)...... 121

x i CHAPTER I

SYNTHESIS AND CHEMISTRY OF 1-(BENZENESULFONYL)-2-

(TRIMETHYLSILYL)CYCLOPROPANE

I. Statement of the Problem.

1-(Benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl) (2, Scheme 1) and 1-

(benzenesulfonyl)-l ,1-{disubstituted)-2-(trimethylsilyl)ethanes (3), prepared readily from 1-

(benzenesulf ony l)-2*(t rimet hy Isily l)ethane (1 ), undergo facile debenzenesulfonyltrimethylsilylation by tetrabutylammonium fluoride (TBAF) or cesium fluoride

(CsF) to give mono- (4) and disubstituted olefins (5).1 The synthetic method is of particular

present interest in that 1 -(benzenesulfonyl)-2-(substituted) -1 -

[(trimethylsilyl)methyl]cyclopropanes (6) are eliminated smoothly by fluoride ion (Equation 1) to yield 1-methylene-2-(substituted)cyclopropanes (7).1a

Scheme 1. Synthetic Utility of 1-(Benzenesulfonyl)-2- (trimethylsilyl)ethane (1)

. n-BuLiULI I SOoPh 1. n-BuLi ^ M e 3 S i ^ | " — M e g S i ^ ^

TBAF TBAF

4 1 Ph02S. A SiMe3 )< TBAF R (1) V VH THF, 65 C H H H H 6

Study is now made of syntheses of (E)* and (Z)-1-(benzenesulfony()-2-

(trimethylsilyl)cyclopropanes (8), their conversions to varied (E)- and (Z)-1-(benzenesulfonyl)-1-

(substituted)-2-(trimethylsilyl)cyclopropanes (9) and posssible eliminations of 9 by fluoride ion reagents to give various 1-(substituted)cyclopropenes (10, Scheme 2). A principal objective of this research is to develop an efficient general method for preparing difficultly accessible 1*

(substituted)cyclopropenes (10). As will be seen, this research also became directed to synthesis and study of other novel benzenesutfonylcyclopropanes and their derivatives. The background and the present research accomplisments are described as follows.

Scheme 2. Proposed Research

1. n-BuLi F ®

- MeaSiF, SCfePh -OaSPh 8 9

II. Introduction.

The synthetic utility of 1-(benzenesulfony)-2-(trimethysilyl)ethane (1) has been briefly 2 3 examined by Kocienski and by Eisch ef a/, and exhaustively studied independently by Hsiao and Shechter.1 1-(Benzenesulfonyl)-l-(lithio)-2-(trimethylsilyl)ethane (11), generated quantitatively at -78°C in THF or ethyl ether by deprotonation of 1 with n-butyllithium, reacts with a 3 variety of electrophtles (primary halides, certain secondary halides, aldehydes, ketones, epoxides, acid halides, halogens, silyl halides) to give 1-monosubstituted derivatives 2 which upon elimination by TBAF yield monosubstituted terminal olefins (4, Scheme 3). Furthermore, sulfone 1 can be disubstituted to form 3 by reactions of 2 with n-butyllithium and then the above electrophiles. Fluoride ion eliminations of 3 give disubstituted terminal 5 effectively.

Sulfone 1 is thus an effective synthon for vinyl anion 12 and vinyl dianion 13.

Scheme 3. Synthetic Utility of 1>(Benzenesulfonyl)-2-(trimethylsilyl)ethene ( 1)

.S 0 2Ph n-BuLi, THF ^SC^Ph E ® MeaSi^^^ MeaSK Y' — -78°ToOr* C u I 11

1- ^BuLi, THF, -78°C^ ^ ^ S O . P h

Ei 2. E2® E 2 3

TBAF, THF, 65°C TBAF, THF, 65°C

H E2 4 5 © _ © ® 12 13

Fluoride ion eliminations of derivatives of (E)- and (Z)-1-(benzenesulfonyl)-4-

(trimethylsilyl)-2-butenes (14) to various terminally substituted 1,3-dienes (17, Scheme 4) have 4 o been examined extensively at Ohio State. Deprotonation of 14 by n-butyllithium at -78 C in

THF gives corresponding lithio derivative 15 which reacts with various electrophiles (primary and 4 secondary alkyl halides, acid chlorides, epoxides, and triorg a nometal lo chlorides) to yield monosubstituted derivatives 16 as a mixture of E and Z isomers (Scheme 4). Treatment of 16 with TBAF (two equivalents) at 0° C in THF results in effective debenzenesulfonyltrimethylsilylation to yield (E)-1 -substituted- 1,3-dienes 17. Thus sulfone 14 is an effective synthon for 1-(1,3-butadienyl) anion 16. Proper utilization of sulfone 14 complements existing methods of syntheses of varied 1-(substituted)-1,3-dienes.

Scheme 4. 1-(Benzenesulfonyl)-2-(trimethylsllyl)-2-butenes (14) as a 1-(1,3- Butadienyl)Anion Synthon

SOaPh n-BuLi, THF, -78°C

14 15

H H © SCfePh TBAF, THF. 0°C

E H 17 H

H 18

Sulfone 16 (E = alkyl) can be substituted further with alkyl halides. Reaction of 16 with one equivalent of n-butyllithium at -76°C gives lithio derivative 19 that can be alkylated with primary halides to produce 1,1-disubstituted sulfones 20. Reactions of 20 with TBAF yield 1,1-

(dialkyl-substituted)-(E)-terminal-1,3-dienes (21, Scheme 5) at 0°C in THF. Sulfone 14 is therefore an excellent synthetic equivalent for the 1,1-(1,3-butadienyl) dianion 22. 5 Scheme 5. 1-(Benzenesulfonyl)-2-(trlmethylsilyl)-2-butenes (14) ae a 1,1-(1,3 Butadienyl)dlanlon Synthon

SOzPh TBAF, THF, 0°C

Practical reactions of o-[(trimethylsilyl)methyl]benzyl p-tolyl sulfone (23) as an effective o- quinodimethane synthon have been extensively investigated in this laboratory.5 Thus, parent sulfone 23 is monoalkylated by n-butyllithium in THF or ethyl ether at -78°C and then with various primary, secondary, allyl, and benzyl halides at 20-25°C to give monoalkyl sulfones 24 which can be further alkylated successively by n-butyllithium and alkyl halide to provide various a ,a - dialkylated silyl sulfones 25 (Scheme 6). Of particular interest is that monoalkyl sulfones 24 are not eliminated by fluoride ion. Sulfones 30 (Scheme 7) are produced upon removal of the trimethylsilyl groups from 24 by fluoride, transfer of hydrogens alpha to the sulfone groups in 28, and protonations of 29 on neutralization. However, a,a-disubstituted silyl sulfones 25 eliminate satisfactorily with fluoride ion (Scheme 6) to give o-quinodimethanes 26 that can be trapped effectively by dienophiles to yield tetrahydronaphthalenes 27. 6 Scheme 6. o-[(Trimethyleilyl)methyt]benzyl p-Tolyl Sulfone (23) as en o- Quinodimethane (26) Equivalent

1. n-BuLi 1. n-BuLi

Y—C=C—Z TBAF

SO2 C7 H7 R1

Ri R2 27 25 26

Scheme 7. Protodesilylation of 24

SiMe TBAF

24 28

c h 3

29 30 7 With this extensive background on the work previously done in this goup, exploration of fluoride ion detrimethylsilylbenzenesulfonylation of appropriate 1 -(benzenesulfonyl)-l-

(substituted)-2-(trimethylsilyl)cyclopropanes (9) became of interest for possible syntheses of 1 -

(substituted)cyclopropenes (10, Scheme 8).

Scheme 8. Potential Syntheeee of 1-(Subetituted)cyclopropenee (10)

S02Ph A E 10

Historical

Syntheses and reactions of silyl-substituted cyclopropanes have been recently 0 summarized by Paquette. As background to the present research effort, the literature of preparation and the reactions of 2-(substituted)-1-(trimethylsilyl)cyclopropanes along with other methods of synthesis of cyclopropenes via 1,2-eliminations will be summarized. Syntheses and the chemistry of sulfonyl-substituted cyclopropanes will also be reviewed.

A) Synthesis and Chemistry of 2-(Substitutad)'1>(trimethylsilyl)cyclopropanas.

Halton and coworkers have found that 1,1,2-tribromo-2-(trimethylsilyl)cyclopropane (31)

is eliminated by fluoride ion to yield 1,2-dibromocyclopropene (32, Scheme 9).7 Furan and diphenylisobenzofuran (DPIBF) react with 32 to give Diets-Alder adducts oxo 33 and antfo 35

and 9xo 34 and anefo 36, respectively. 1,2-Dibromocyclopropene (32) also adds to exocyclic Q dienes 37 and 38 to produce 39 and 40, respectively (Scheme 10). of 39 8 Scheme 9. Trapping of 1,2>D(bromocyclopropene (32) with Furan

Br TBAF, THF, -30°C

SiMes Br

| \ ^ R1

Br FU PBr

33 Rt = R2 = R3=R4 = H 35 R 1 = R2 = R3 = R4 = H 34 R! = R2 = Ph, R3 = R4 = (CH)4 36 R t = Rz = Ph, R3 = R4 = (CH)4

and 40 with DDQ in refluxing followed by dehyrobrominations with potassium teri - butoxide in THF at -78°C give 5FFcycloprop[/]isobenzofuran ( 4 1 ) and 5H-cyclopropan[f ]

[2]benzothiophene (42), respectively.

Scheme 10. Trapping of 1,2-Dibromocyclopropene (32) with Exocyclic Dienee

1. DDQ, PhH, 0O°C

37 X -O 2. KOBu*, THF, -78°C

38 X = S 39 X-O (92%) 41 X -0(94%, 55%)

40 X * S (53%) 42 X - S (97%, 81%) 9

Chan and Massuda have found that 1,2-elimination of 1,1-dibromo-2-

(trimethylsilyl)cyclopropane (43, Scheme 11) occurs readily with potassium fluoride in diglyme at

80°C to generate 1-bromocyclopropene (44) as evidenced by the presence of a NMR g doublet at 5 1.6 and a triplet at 5 7.2 in the product. Further proof was also provided by trapping

44 with 1,3-diphenylisobenzofuran (DPIBF) to give exo adduct 45 exclusively and with furan to yield endo 46 and exo 47 isomers in a 2:3 ratio.

Scheme 11. Trapping of 1-Bromocyclopropene (44) with Furan and DPIBF

Br. Br Ph KF, diglyme, DPIBF SiMe3 80°C H Ph 43 46

Q

A H 46 47

Billups etal. have reported that 1-bromo-2,2-dichloro-1-(trimethylsilyl)cyclopropane (49), prepared from a-(bromovinyl)trimethylsilane (48) and , reacts with fluoride ion to give 1-bromo-2-chlorocyclopropene (50), a moderately stable compound, which is trapped with 51 to give 52, an important intermediate for synthesis of 1H -cyclopropa[b ]phenanthrene

(53) as summarized in Scheme 12.10 1 0

Scheme 12. Synthesis of IH-Cyclopr (53)

CI3CC02Na TBAF, THF

Me3Si glyme:digylme Me3Si Cl -20°C a- ci M t (10:1) 49 50

SI

52 53

Spiropentadiene (bowtiediene, 58), a compound of considerable interest, has been synthesized by Billups and Haley.1 1 Reaction of the tosylhydrazone of bis(trimethylsilyl)propynone (54) with in a two phase solvent system at low pH gives allene 55 which on treatment with chlorocarbene, generated from and , affords chloro-bis[(trimethylsilyl)methylene]cyclopropane 56 in low yield

(Scheme 13). Addition of dichlorocarbene to 56 provides 57 in 6% yield, double elimination of which by fluoride ion in the gas phase at low pressure gives 58 which is trapped by cyclopentadiene to form Diels-Alder adduct 59 in 10% yield. 11

Schema 13. Synthesis and Trapping of Spiropentadiene (58) with Furan

H SiMe3 NNHTs NaCNBH3 MfigSi ‘ SiMe3 sulfolane/DMF H SiMe3 SiMe- 54 pH1 Cl 55 56

MeU TBAF = 7 O

10 mtorr _ \ -78°C 25°C 59 57 58

Reactions of methyl phenyl sulfone and n-pentyl phenyl sulfone (60) with n-butyllithium and then triphenylsilyloxirane (61) yield alcohols 62 which on mesylation (MsCI, pyridine) to 63 and then treatment with sodium bis(trimethylsityl)amide in THF at -20°C give cyclopropyl 12 derivatives 64 in excellent yields (Scheme 14). Of maior importance to the research of this dissertation is that 64 reacts with n-butvllithium (1 eouiv) in THF at room temperature to oive cycloprooenes 65 in superb yields. Interestingly, the reactions of 64 with fluoride ion were not

reported. 1 2 Scheme 14. Synthesis of 1-(Triphenylsilyl)cyclopropene (65)

/ \ n - BuLi t H O ^ ^ ^ R 2 MsCl PhS02R + f ~t-i ir ------60 PtbS^ SiPh3 S02Ph pyridine 61 R = Me 62 R = n-C5H12 Ri = H. R2 = MeM< (71%) = H, Rg — (66%)

Ms° v / \ ^ r2 NaN(SiMe3)2 « n-BuLi '*1 ______‘ o :^ SiPh3 S02Ph THF. -20°C P^aS* So2Ph THF, 2S°C r Sjph3 63 64 66

R, = H, R2 = Me (94%) R = Me (90%) R = Me (90%) R , = H, R2 = n-C5H12 (96%) R = "-C5H1? (98%) R = n-C5H12 (90%)

B) Other Syntheses of Cyclopropenes via 1,2-Eliminatlons.

1) Dehydrohalogenations.

The most commonly employed procedure for preparing cyclopropenes by 1,2- eliminations involves dehydrohalogenation with potassium ferf-butoxide in tetrahydrofuran and dimethyl sulfoxide. Reaction of 7,7-dichlorobicyclo[4.1.0] (66) with potassium ferf-

butoxide in DMSO forms bicycloheptene 67 which is trapped by 1,3-diphenylisobenzofuran

(DPIBF) to give Diels-Alder adducts 68 as a 1:1 mixture of endo:»xo isomers in 91% yield 1 3 (Equation 2). Potassium ferf-butoxide supported on silica is very effective for such

dehydrohalogenations in the vapor phase. Passage of bromocyclopropane 69 over the base-

Ph KOBu' DPIBF (2) DMSO. 25° C Ph 66 67 68 1 3 impregnated support at 160°C leads to spirocyclopropene 70 in 85% yield (Equation 3).14

KOBu1, SiC>2 (3)

160 °C

69 70

2) Vicinal Dehalogenationa.

1,2-Dimethylcyclopropene (72) is preparable (Equation 4) by reductive elimination of cis-

1,2-dibromo-1,2-dimethylcyclopropane (71) with fert-butyllithium. Trapping of 72 with 15 diphenylisobenzofuran (DPIBF) gives 0x 0 adduct 73 exclusively in 80% yield. 1-fert-butyl-1- chloro-1,1-dihalocyclopropanes (74) are 1,2-dehalogenated by methyllithium at -40°C to

Ph f-BuLi DPIBF (4) THF, -78°C Me Me Me Me Me Ph Me 71 72 73

1 6 yield 1-ferf-butyt-2-halocyclopropenes (75) as isolable products (Equation 5)

Similarly, 1,1,2,2-tetrachtoro-3,3-dimethylcyclopropane (76) and methyllithium give 1,2-dichloro-

3,3-dimethylcyclopropene (77) as a stable product in reasonable yields (Equation 6).17

MeLi, Et 2 O (5) -40° C f-B u

X = Br (52%) X = Cl (29%) 1 4

Me Me

MeLi, EtjO (6) -40° C Cl 76 77

3) Selenide or Selenoxide Eliminations.

1 (Cyanocyclopropyl) phenyl selenoxide (78) undergoes selenoxide elimination in refluxing in the presence of to give 1 -cyanocyclopropene (79) which is 18 capturable as Diels-Alder adduct 80 in 45% yield (Equation 7). The tetrafluoroborate salt 82, prepared by silver ion assisted methylation of selenide 81, reacts with potassium fe/ 1 -butoxide in

THF to give /-/-cyclopropa[/]phenanthrene (83) which is trapped by furan to give cycloadducts 84 19 and 85 (Scheme 15).

CN NC Se(Q)Ph CN anthracene (7) A 140°C A 80 78 79 1 5

Scheme 15. Synthesis and Trapping of H>cyclopropa[/]phenanthrene (8) with Furan

KOBu* SeMe EfeO THF,

81 8 2 8 3

8 4 8 5

C) Synthesis and Chemistry of Cyclopropyl Sulfones.

1) Intramolecular Alkylations. 20 Intramolecular alkylations of a-sulfonyl carbanions have been extensively studied. As a classic example, benzenesulfonylcyclopropane ( 8 8 , Scheme 16) is obtained by reaction of potassium fe/t-butoxide with 3-chloropropyl phenyl sulfone (87) as prepared from sodium thiophenoxide and 1-bromo-3-chloropropane followed by oxidation of 3-chloro-1-

2 1 (thiophenoxy) ( 8 6 ) with 30% aqueous hydrogen peroxide in refluxing acetic acid.

[(Phenylsulfonyt)methylene]ditithium (89), a novel cyclization reagent generated from methyl phenyl sulfone and two equivalents of n-butyltithium, reacts with 1 ,2 -dichloroethane to form 22 benzenesulfonylcyclopropane (88 , Equation 8 ) in 60% yield. 1 6 Scheme 16. Synthesis of Benzenesulfonylcyclopropene (88)

30% aq H2 O 2 PhSNa + Br' PhS HO Ac

KOBu

S0 2 Ph 88

2 n - BuLi "Cl PhS02MB ------► PhS0 2 CHLi2 ► I —S02Ph (8 ) THF, 0°C m 89 8 8

a,p-Unsaturated carbonyl compounds may be converted to cyclopropyl phenyl sulfones 23 by intramolecular ring-closures of co-halogenoalkyl sulfones. Michael additions of sodium thiophenoxide to a,p-unsaturated carbonyl compounds 90, acidification followed by reductions with sodium borohydride give phenylthio alcohols 91 which upon oxidation to their benzenesulfonyl alcohols 92, tosytation, and cyclization with LDA in THF result in cyclopropyl phenyl sulfones 93 in excellent yields (Scheme 17).

Scheme 17. Synthesis of Cyclopropyl Sulfones 93

© FT 1 ■ PhSNa; H p^g R‘ H2 O2 . HOAc Ph02S R‘ w 2 NaBHj R OH R OH 90 91 92

R = H, R* = H (100%) 2. LDA, THF, -78^ R‘ R = H. R' = Me (99%) R = Ph, R‘ = H (100%) 93 1 7

1-Acyl-1 -(benzenesulfonyl)cyclopropanes (95) are preparable in moderate yields

(Equation 9} by one-pot base-catalyzed double alkylations of (1-keto sulfones 94 with 1 ,2 - 24 dibromoethane in DMF.

------► O) R K2 C 0 3, DMF

94 96

R = C3 H5 (50%) R = CHMe2 (55%) R = C6Hn (53%) R = Ph (56%)

Tanaka and Suzuki have recently developed the following efficient syntheses of 25 cyclopropyl sulfones (Scheme 18). Reactions of benzenesulfonylmethyllithium (89) with 1 ,2 - epoxyalkanes (96) give monolithio sulfones 97, which when followed by sequential additions of benzenesulfonyl chloride ( 1 equiv) and n-butyllithium, afford trans cyclopropyl phenyl sulfones

98. Similarly as in Scheme 19 and Table 1, 1-alkyl-substituted sulfones 100, prepared by

alkylations of dilithio derivatives of 3-benzenesulfonyl-1 -propanol (99), react sequentially with n-

butyllithium, benzenesulfonyl chloride, and n-butyllithium, to form 1 -alkyl - 1 -

(benzenesulfonyl)cyclopropanes ( 1 0 1 ) in good yields. 1 8

Scheme 18. Synthesis of Cyclopropyl Sulfones 98

O

n-BuLi ^ ® PhS02Me ------► PhS0 2 CH2Li ______H THF. -70°C 8 8

1. PhS02CI Ph02S 2. n -BuLi Ph02S

8 8

R = Me (75%) r = n-C6 H1 3 (84%)

R = n-C4 H9 (71%) R = Ph (75%)

Scheme 19. Synthesis of Cyclopropyl Sulfones 101

1. n -BuLi (2 eq)

Ph0 2 S''OH Ph02S OH THF-HMPA 99 100 2. RX

1. n-BuLi (1.1 eq), THF

2. PhS02CI S 02Ph

3. n-BuLi (1.1 eq) 101 1 9

Table 1. Reactions of 99 to Give 100 and Reactions of 100 to Give 101

RX 100 (% Yield) 101 (% Yield)

n- CsHnBr 69 81

n-C7 H i5Br 72 74

n -Ci2 H2sBr 74 6 8

62 73

2) Intramolecular Michael Additions and Displacement-Cyclizations.

2-Functionally-substituted-1-(benzenesulfonyl)cyclopropanes are preparable by Michael additions followed by intramolecular displacement-cyclization. Thus, a-bromovinyl phenyl sulfone

(102) undergoes Michael additions of 1 ,3-dicarbonyl compounds 103 in the presence of followed by displacement ring closure to give 1,1 -diacyl-3-

2 g (benzenesulfonyl)cyclopropanes (104) in good yields (Equation 10).

S 0 2Ph O O NaH (10) R2 Br R, ^ R2 o 1 0 2 103 104

Ri = R2 = OEt (54%) R,= R2= Ph (69%)

Ri = Ph, R2 = OEt (69%) Ri = Ph, R 2 = Me (69%) 20

A similar method of synthesis of cyclopropyl sulfones 106 is Michael reaction of the sodium salt of diethyl malonate with a-chlorovinyl sulfone 105, intramolecular proton transfer 27 followed by intramolecular displacement of chloride (Scheme 20).

Scheme 20. Synthesis of Cyclopropyl Sulfones 106

Cl 9' © Cl NaCH(C02 Et) 2 \& Nay A r ^ A A t. Ar>. S 0 2 Ph" S02Ph ■ @V ^ s o 2Ph THF CH(C0 2 Et) 2 Na 3C(C02 Et) 2 105

Ar

S 0 2Ph 106

Further, Grignard reagents prepared from allyl bromide, propargyl bromide, 1-bromo-3- methyl-2-, bromobenzene, and benzyl chloride, respectively, react with 1-(3-bromo-1- propenyl) phenyl sulfone (107) to give (2'Substituted-cyclopropyl) phenyl sulfones 108 in good 28 yields (Scheme 21). Such syntheses of cyclopropyl sulfones 108 are not successful with methyl, ethyl and fert-butyl Grignard reagents. 21 Schema 21. Synthesis of Cyclopropyl Sulfones 108

H S 0 2Ph RMgX S 0 2Ph R\ /-sc S 0 2Ph H MgX A Br H 107 108

R = H2 C=CHCH 2 (76%) = Ph (40%)

= HC=CCH 2 (50%) = PhCH2 (54%)

= H2C = CHCMe2 (55%)

Of particular interest is that aryl 2 -aryl- 1 -vinyl sulfones (109) are efficiently cyclopropanated by dimethylsulfonium methylide ( 1 1 0 ) in dry dimethyl sulfoxide to give frans- 1 -

(aryl)-2-(arytsulfonyl)cyclopropanes (111, Equation 11 ) . 2 9

A r02S u

> = < H - h 2 c = s m 6 2 dmso . (11) H Ar 109 110 111

Ar = Ar' = Ph (8 8 %) Ar = 4-CIC6 H4, Ar' = 3-CIC6 H4 (74%)

Ar = 4-BrC6 H4, Ar'= 4-CIC6 H4 (80%) Ar = 4-MeC 6 H4, Ar = 2-BrC6 H4 (72%)

3) Phase-Trensfer Cycllzation Mathodology.

Cyclopropyl sulfones can also be prepared using phase-transfer cyclization methods.

Thus, allyl p-toluenesulfonate (112) and 1,2-bromoethane are converted to 1 -allyl-1 -(p- toluenesulfonyl)cyclopropane (113) by triethylbenzylammonium bromide (TBABr) in aqueous sodium hydroxide (Equation 1 2 ) . 3 0 Alternatively, reactions of phenylsulfonylacetonitrile (114) and ethyl phenylsulfonylacetate (115) with 1 ,2 -dibromoethane in the presence of benzyltriethylammonium chloride (BTEA) and sodium hydroxide afford 1-

(benzenesulfonyl)cyclopropanecarbonitrile (118) and ethyl 1* 22 phenylsulfonylcyclopropanecarboxylate (117), respectively (Equation 13).31 Further, cyclopropyl p-keto sulfones 120 are obtained from reactions of phenacyl sulfonium salts 119 and vinyl sulfones 118 in aqueous sodium hydroxide and benzyltriethylammonium chloride

(Equation 14).32

Tn|fv c 50% aq NaOH Tol0 2S ^ ^ ______: ______(12)

TBABr, Bi

112 113

50% aq NaOH S 02Ph PhS0 2 CH2R (13) .Br BTEA, b i 114 R = CN 116 R = CN (71%) 115 R = C02Et 117 R = C 0 2Et (67%)

Me2 B? Ar 119 ^ S ^ S 0 2Ar (14) Ar 118 BTEA, 50% aq NaOH 120 u

Ar = Ar = Ph (52%) Ar = Ar'= 4-CIC6 H4 (87%)

Ar = Ph, Ar = 4-CIC6 H4 (63%) Ar = 4-MeC6 H4, Ar' = 4-CIC6 H4 (57%)

4) Additions of Phsnylthlocarbsnss to Olefins.

Of importance to the present research is that arylsutfonylcyclopropanes are preparable by oxidation of arylthiocyclopropanes as obtained by addition of phenylthiocarbenes to electron rich olefins. Thus, Reddy and Balaji have synthesized cis- 1-(arylsulfonyl)-2-phenylcyclopropanes 2 3 124 by reactions of and arylthiocarbenes 122, as generated from aryl chloromethyl sulfides 1 2 1 and excess potassium terf-butoxide. to give cis - 1 -(arylthio)- 2 -phenylcyclopropanes

(123) which are then oxidized with hydrogen peroxide (Scheme 2 2 ).33

Scheme 22. Synthesis of Cyclopropyl Sulfones 124.

^ P h ArSCH2 C, + KOBu* ArSCHCH ]

121 122

H 2 0 2, HOAc

Ph SAr S 0 2Ar 123 124

Ar = Ph (89%) Ar=4-MeC6 H4 (82%)

Ar = 4-CIC6 H4 (79%) Ar = 4-N0 2 C6 H4 (84%)

Addition of chloromethyl phenyl sulfide to potassium terf-butoxide in gives phenylthiocarbene which adds to the more substituted double bond of 1 ,1 -dimethylallene and heating of the intermediate at 1 2 0 °C undergoes thermal isomerization to sulfide 125 and subsequent oxidation gives 1-{benzenesulfonyl)-2-(2-propylidene)cyclopropane (126, Scheme

23).34

Scheme 23. Synthesis of 2-Methylene-1-cyclopropyl Sulfones 126

Me Me Me Me Me Me

Y 1 PhSCH2 CI, KOBu* || OXONE

L * j r ~ A . - 125 125 24

III. Results and Discussion.

The present research initially involved (1) development of an efficient large scale synthesis of 1 -(benzenesulfonyl)- 2 -(trimethylsily!)cyclopropane ( 8 ), (2 ) transformations of 8 to varied t-(benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl)cyclopropanes (9), (3) study of practical eliminations (detrimethylsilylbenzenesulfonylation) of cyclopropanes 9 by fluoride ion sources to 1-(substituted)cyclopropenes (10), and (4) possible elaboration of the chemistry and synthetic utility of cyclopropenes 10. Because of the difficulties in preparing and handling and the instabilities of cyclopropenes 1 0 , knowledge of their behavior is limited.

8 9 10

Retrosynthetlc Considerations for Synthases of 8.

1-{Benzenesulfonyl)-2-(trimethylsilyl)cyclopropane ( 8 ) can be envisioned to be preparable from precursors as exhibited in Scheme 24. Methylene (CH 2 ) or ’methylene transfer"

additions to (1) (E)-1-(phenylthio)-2-(trimethylsilyl)ethene (127, n = 0) and oxidation and/or ( 2 )

(E)-1-(benzenesulfonyl)-2-(trimethylsilyl)ethene (128, n = 2 ) may be viable routes to 8 . Similarly, metal-catalyzed additions of trimethylsilyldiazomethane (129) to (1) phenyl vinyl sulfide (130, n =

0) and oxidation and/or (2 ) phenyl vinyl sulfone (131, n » 2) are possibilities. Metal-catalyzed reaction of trimethyl(vinyl)silane (133) and phenylsulfonyldiazomethane (132) is an alternate pathway. Further, anionic cyclization reactions of 1-(benzenesulfonyl)-2-

(trimethylsilyl)cyclopropane (134) with leaving groups at the 3-position are other promising options. 25 Scheme 24. Retrosynthetic Syntheses of B

S<0)nPh / ----- + "CH2" Me3Si 127 n = 0

128 n = 2

LG o f S b < ^ S iM e 3 Ph02S ''^ r''^ R 133

SiMe3 +

134 PhS0 2 CHN 2

132

-i^StOJnPh + Me3 SiCHN2

130 n = 0 1 2 9 131 n = 2

Methylene Additions to (E)-1-(Phenylthio)>2-(trimethylsilyl)ethene (127) and

(E)-1 -(Benzenesulfonyl)-2-(trimethylsllyl)ethene (128).

Study was initiated of varied methylene transfers to (E)-1 -(phenylthio)-2-

(trimethylsilyl)ethene (127) and (E)-1-(benzenesulfonyl)-2-(trimethylsilyl)ethene (128). Olefin

127 was conveniently prepared from photolysis of (trimethylsilyl) and thiophenol in benzene (Scheme 25) in 54% yield . 3 5 Silane 128 (Scheme 25) was synthesized in 72% yield via elimination of 2-(benzenesulfonyl)-l-chloro-1-(trimethylsilyl)ethane (135) as prepared by 26 addition of benzenesulfonyl chloride to trimethyl(vinyl)silane (133) in the presence of cuprous chloride as described by Calas et al.3®

Scheme 25. Syntheses of (E)-1-(Phenylthlo)-2-(trimethylsilyl)ethene (127) end (E)*1*(Benzenesulfonyl)-2-(trimethylsilyl)ethene (128)

hv, PhH PhS H PhSH + H— = — SiMe3 ______► V = Z

H SiMe3 127

PhS02CI Cl

CuCI J L .S 0 2Ph Et3 N.PhH Ph02S H ^ SiMe3 ------► Me3Si ► S ~ \

CH2 CI2 w h SiM®3 133 135 128

Methylene additions to 127 and 128 were investigated as follows. Reagents employing diiodomethane with Zn(Cu) 3 7 or Zn(Ag) 3 8 couples, Me 3 AI, 3 9 Et2 Zn, 4 0 and Cu4 1 failed to result in addition of methylene to 127 and 128 (Equation 15) under varied experimental conditions (-

78°C, room temperature, and in refluxing THF, ether, DMSO). Palladium acetate catalyzed transfers of diazomethane to 127 and 128 using Vorbruggen's4 2 procedure resulted in efficient recovery of the initial olefins. Finally, the Corey 4 3 and Reddy 4 4 sulfur ylides dimethyloxosulfonium methylide and dimethylsulfonium methylide, respectively, did not add to vinyl sulfone 128. The syntheses were presumed to fail because the trimethylsilyl group prevents methylene transfer to the trana double bonds. 27 S(0)nPh ■CH2" (15) M e3Si "conditions" Me3Si S(0)nPh 127 n = 0

128 n = 2 136 n = 0

It was then hoped that the c/s olefin, (Z)-1-(p-toluenesulfonyl)-2-(trimethylsilyl)ethene

(138), would minimize the steric problems and allow nucleophilic methylene transfer reagents to add to the lesser hindered olefin face. of p-tolyl 2-(trimethytsilyl)ethynyl sulfone

(137), prepared from reaction of bis(trimethylsilyl)acetylene, p-toluenesulfonyl chloride, and aluminum chloride , 4 5 over Lindlar's catalyst afforded c/s-silane 138 (Scheme 26). Additions of dimethyloxosulfonium and dimethylsulfonium methylides and diazomethane to 138 unfortunately met with failure; 138 was recovered efficiently. Methylene additions to silaolefins

127 and 128 were abandoned, and an alternate route to 8 was sought.

Scheme 26. Preparation of (Z)-1-(p-Toluenesulfonyl)-2-(trimethylsilyl)ethene (1 3 8 )

C7 H7 S02CI u Air, H2, Pd-BaS04 H H Me3Si j SiMe3 ?---- ► Me3Si - ~ S 0 2 C 7 H7 ------\ = ^

CH2 CI2 MeOH Me3Si S 02 C 7 H7 137 138

Trlmethylsilyldlazomethane (129) Transfer to Sulfur Olefins.

Other metal-promoted carbenoid syntheses of 8 were then investigated.

Trimethylsilyldiazomethane 4 6 (129), prepared from trimethylsilylmethyl chloride

(139) and diphenylphosphoryl azide (Equation 16), undergoes rhodium diacetate 4 7 or cuprous chloride 4 6 catalyzed transfers to phenyl vinyl sulfide (130) to give 1 -(phenylthio)- 2 - 28

(trimethylsilyl)cyclopropanes (140, Equation 17) in 18% and 8 % yields, respectively. Addition of trimethylsilyldiazomethane (129) to the electron deficient olefin, phenyl vinyl sulfone (131) as possibly catalyzed by palladium dichloride in refluxing benzene failed (Equation 18).4®

1 . (Ph0)2 P(0)N 3 Me3 SiCH2MgCI ------Me3 SiCHN 2 (16) © 139 2. H30 12g

Rh2 (OAc)4, CH 2 CI2 Me3 SiCHN2 + < ^ SPh or SiMe3 129 130 CuCI, C5 H 1 2 140

r a w ? , r n n t H / \ Me3 SiCHN 2 + <^s02Ph — ------\ / \ <1 8 >

1® 131 8

Addition of p>Toluenesulfonyldiazomethane (141) to Trimethyl(vlnyl)ailane

(133).

The next approach to synthesis of 8 involved dirhodium tetraacetate promoted transfer of p-toluenesulfonyldiazomethane (141, Scheme 27) to trimethyl(vinyl)sitane (133). Following the method of van Leusen.SO reaction of p-toluenesulfonyl fluoride and triphenylphosphonium methylide in tetrahydrofuran provided p-toluenesulfonylmethylenetriphenylphosphorane (142) which, when treated with p-toluenesulfonyl azide, afforded p-toluenesulfonyldiazomethane

(141, Scheme 27). Dirhodium tetraacetate4 7 catalyzed addition of 141 to trimethyl(vinyl)silane

(133) in methylene chloride gave 1-(p-toluenesulfonyl)-2-(trimethylsilyl)cyclopropane (143) as an air stable, handleable yellow oil in only 21% yield. The E/Z ratio was determined to be 67:33 by the ratio of the areas of the trimethylsilyt 1H NMR singlets at 5 -0.12 and 5 0.22. All attempts to improve the yield of 8 were unfruitful. A better large scale method of synthesis of 8 was needed. 29

Scheme 27. Preparation of p-Tolueneeulfonyldiazomethane (141) and Reaction of 141 with Trimethyl(vinyl)eilane (133) to Give 1-p-(Tolueneaulfonyl)-2- (trimethylsilyl)cyclopropane (143)

P ^ P = C H 2 p-TsN3 C7 H 7 S 0 2F ------► C 7 H 7 S 0 2 CH=PPffc

THF, 25°C ^ CH 2 CI2

< ^ ^ S i M e 3 (133)

Rh2 (OAc ) 4 c 7 h 7 s o 2 c h n 2

141 CH2 CI2, 35°C C 7 H7 S 0 2 S i M ® 3 143

Anionic Intramolecular Diaplacementa of 1-(Benzeneaulfonyl)>3*(subatituted)-2-

(trimethylsilyl) (134).

Syntheses of 147 by anionic cyclization reactions of 1-(benzenesulfonyl)-2-

(trimethylsilyl)alkanes (134) with leaving groups at the 3-position were then attempted. Reaction of methyl phenyl sulfone ( 2 equiv) and n-butyllithium ( 2 . 1 equiv) followed by cl»- 1 -propyl- 2 -

(trimethylsilyl)oxirane 5 1 (144, 1 equiv) and boron trifluoride etherate5 2 (2 equiv) using the procedure outlined by Wicha 5 3 gives (2R, 3R)-1-(benzenesulfonyl)-2-(hydroxy)-2-

(trimethylsilyl) (145, Scheme 28) in 76% yield. The single diastereomer pair (145) is formed as expected by attack of lithiomethyl phenyl sulfone on the a-carbon containing the trimethylsily! moiety in 144 with inversion of configuration. The sterochemistry of 145 is consistent with the 1H NMR of similar compounds . 5 3 Conditions were then examined for the conversions of 145 to alcohol derivatives 146 which are possibly cyclized by lithium diisopropylamide (LDA, THF, -78°C to RT) to cyctopropanes 147. Attempts to transform alcohol

145 to its (1) tosylate 146 (X = Ts, 55%) by p-toluenesulfonyl chloride (p-TsCI), 4- dimethylaminopyridine (DMAP), and triethylamine (Et 3 N), (2) iodide 146 (Z = I, 6 8 %) by 30 generating iodotrimethylsiiane in situ with trimethylsilyl chloride (TMSCI) and Nal using the method of Olah54, and (3) mesylate 146 (X = Ms, 70%) by methanesulfonyl chloride and triethylamine however all give (E)-1-(benzenesuifonyl)-2- (148), a consequence of

Peterson eliminations (Scheme 29). The potential for such ring closures was not studied further.

Scheme 28. Attempted Anionic Cyclizations of 146 to 147

pTsCI, DMAP, Et3N OH or 1. n-BuLi, THF,-20°C TMSCI, Nal, CH3CN

or - a -

144 MsCI, Et3 N, CH 2 CI2

BF3 OEt2 3. H20

c 3 h 7

LDA, THF. -7B°C to 25°° PhS0 2 ------i t

SiMe3

146 X = Ts, I, Ms 147

Scheme 29. Peterson Eliminations of 145

OH pTsCI, DMAP, Et3N or TMSCI, Nal, CHaCN PhS02' PhS02' or SiMe3 MsCI, Et3 N, CH2 CI2 148 145 31 Synthesis of - and (Z)-1-(Benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes

(8 ).

After the previous syntheses of 8 had failed, a multi-step, high yielding route was found as outlined in Scheme 30. Reaction of phenyl vinyl sulfide 5 5 (130) with (phenylthio)methylene as generated by phase transfer from chloromethyl phenyl sulfide 5 5 (149), benzyltriethylammonium chloride (BnNEt 3 CI), 50% aqueous NaOH, and methylene chloride at room temperature furnishes (Z)-1,2-bis(phenylthio)cyclopropane (150) in 97% yield following the preparation detailed by Nakayama. 5 7 The sterochemistry of 150 is assigned c/s based on the

1H NMR (see Figure 1) of three multiplets at 5 1.01 (C-3 hydrogen), 1.76 (C-3 hydrogen), and

2.77 (C- 1 and C- 2 hydrogens) and is in agreement with the literature. 5 7 If the product was the trmns isomer the two methylene hydrogens on the C-3 atom would be equivalent and there would be only two 1H NMR multiplets. Of note also is that Boche 5 5 and Reddy 3 3 report that additions of arylthiocarbenes to styrene and to ethyl vinyl ether provide c/s - adducts exclusively.

Additions to the various olefins to give c/s-adducts may arise from coordination of the phenylthio moiety of the carbene with electron-donor substitutents on the olefins or/and

(phenylthio)methylene might be significantly carbenoid-like by association with the bulky benzyltrimethylammonium ion and thus the stereochemistry of addition is controlled by the cation rather than the carbene.

Various preparations of disulfide 150 were clean by 1H NMR and the product was oxidized without purification by 30% aqueous hydrogen peroxide in refluxing acetic acid to (Z)-

1 ,2 -bis(benzenesulfonyl)cyclopropane (151), a white solid, in 81% yield. Disulfone 151 is assigned as c/s on the basis of its 1H NMR multiplets at 8 1.76 (C-3 hydrogen), 2.48 (C-3 hydrogen), and 2.93 (C-1 and C-2 hydrogens) as shown in Figure 2. Stereochemistry is therefore retained in oxidation of 150 to 151.

Addition of n-butyllithium (1.1 equiv) to 151 and reaction with chlorotrimethylsilane give

(Z)-1,2-bis(benzenesulfonyl)-1 -(trimethylsilyl)cyclopropane (152, 65%) as a tan-white solid. The 32 assignment of disulfone 152 as (Z-) (its sulfonyl groups are cla) is based on nuclear Overhauser enhancement (NOE) experiments; irradiation of the trimethylsilyl group at 8 0.19 gives a 1.5%

Scheme 30. Synthesis of (E)- and (Z)-1-(Benzenesulfonyl)-2- (trlmethylsilyl)cyctopropanes (8)

_ _ 50% aq NaOH, CH2 CI2 H PhSCH2CI + <^SPh ------:----- —Zm*

148 130 BnNEt 3 CI, 25°C phS 150

30% aq H2 O2 1. n-BuLi, THF, -7B°C

HO Ac, 110°C Ph02S 2. Me3SiCI

SiMe3 6 % Na-Hg, MeOH

Ph02S SOjPh NaHP04H20.25°C M#jg 152

enhancement of the NMR of the C-2 methine hydrogens at 5 3.57. Reductive desulfonylation of

152 by excess 6 % sodium amalgam buffered with disodium hydrogen phosphate monohydrate in methanol at ambient temperature according to the method by Trost5 9 yields (E)- and (Z)- 1 -

(benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes ( 8 , 70%) as a colorless oil. The E/Z ratios of 8 in different preparations range consistently from 76:24 to 80:20 as determined by the ratios of the areas of the 1H NMR resonances of the trimethylsilyl groups at 6 -0.15 and 5 0.19. The E/Z stereochemistries of 8 are deduced from NOE data; irradiation of the trimethylsilyl group at 6-0.16 gives a 8.4% enhancement at 6 2.20 assigned to the methine sulfonyl hydrogen of the (E)- isomer. The (Z)- isomer is thus assigned from the trimethylsilyl 1H NMR peak at 8 0.19. 33

Cyclopropanes 8 are presumed to be formed (Scheme 31) by electron transfer from sodium amalgam to 152 to yield radical anion 153 which loses the benzenesulfinate anion to form radical

154 and then reaction of 154 with sodium amalgam to give anion 155 which is quenched by methanol. The trimethylsilyl group thus accelerates formation of 155. Protonation of 155 to

yield (E)- rather than (Z ) - 8 appears to be stericalty controlled.

i

Figure 1. 1H NMR of the Upfield Region of (Z)-1,2-Bis(phenylthio)- cyclopropane (150).

3.5 3.0 2.5 2.0 1.5

Figure 2 . 1H NMR of the Upfield Region of (Z)-1,2-Bis(benzenesulfonyl)- cyclopropane (151). 34 Scheme 31. Reaction of 152 with Sodium Amalgam

h ,SiMe3 Na-Hg SiMe3 ' PhSO p h ,SiMe3 Ph02S S 02Ph MeOH Ph02S lS02Ph ph02g 152 153 154

Na-Hg H ,SiMe3 MeOH

Ph02S Ph02S e SiMe3 155 (E) > (Z)

Reactione of Fluoride Ion with (E)- and (Z)-1-(Benzenesulfonyl)-2-(trlmethylsflyl) cyclopropanes (8).

Reactions of 8 with TBAF were then investigated in attempts to prepare cyclopropene

(156, Scheme 32). Cyclopropene (156) is a difficultly handleable, unstable gas. The strained cycloolefin polymerizes at room temperature, is storable for short periods at -tO°C in dilute carbon tetrachloride solution but can be kept as a solid at liquid nitrogen temperature (-196°C).60

Because of its strain, cyclopropene (156) behaves effectively as a dienophile in [4 + 2} cycloadditions with 1,3-butadiene, furan, and diphenylisobenzofuran (DPIBF ) . 6 1

Scheme 32. Reaction of 8 with Fluoride Ion in the Presence of DPIBF

,H TBAF, THF DPIBF

A S02Ph DPIBF 8 156 157 35

In the present study, reactions of 8 and TBAF (2 equiv) in different dry solvents (benzene and THF) at varied temperatures (-40°C, 0°C, and 25°C) in the presence of DPIBF (1 equiv) all give benzenesulfonylcyclopropane ( 8 8 ) in approximately 60% yields. There was no evidence for generation of 156. Failure to produce 156 and then 157 is explained by reaction of 8 with fluoride ion by a stepwise mechanism involving desilylation of 8 to anion 158 which becomes protonated to 8 8 or undergoes isomerization by proton transfer to form stabilized a-sulfonyt anion 159 which then converts to 8 8 (Scheme 33).

Scheme 33. Protodeeilylation of 8

H TBAF

MeaS 8 158

H Sp2ph 88

158

Study was then initiated of synthesis of derivatives of 8 containing substituents in the 1 - position as in 9. Such varied 1-(benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl)cyclopropanes

(9) upon treatment with fluoride ion would stop a-proton transfer as in 158 to 159 and possibly facilitate desirable eliminations to give more stable and handleable1 -(substituted)cyctopropenes

(10, Scheme 34). 36 Scheme 34. Transformations of 8 to 9 to 10

MeaSi S02Ph MegSi S02Ph

Generation of 1 -Lithio-1-(benzenesulfonyl)-2-(trimethylsilyl)cyclopropane <160).

Study was then initiated of proper conditions for generation of 1-tithio-1-

(benzenesulfonyl)-2-(trimethylsilyl)cyclopropane (160). 1 -(Benzenesulfonyl)-2-

(trimethylsilyl)cyclopropane ( 8 ) is found to be converted rapidly and efficiently (Equation 19) by one equivalent of n-butyllithium at -78°C in THF to 160 as a clear bright yellow solution. Lithio sulfone 160 is stable in THF for several hours at room temperature or reflux. Neutralization results in total recovery of 8 upon work-up. Reaction of 160 with deuterium oxide affords (E)- and

(Z)-1-(benzenesulfonyl)-1-(deutero)-2-(trimethylsilyl)cyclopropanes (161) in 100% yield in a ratio of 66:14. Formation of (E)- rather than (Z)-161 indicates that protonation of 160 gives preferentially the lesser strained product. The stereochemistries of 161 were determined by integration of the 1h NMR resonances of the trimethylsilyl absorptions at S -0.12 and 0.43, respectively. The 1H NMR (200 MHz) of 161 shows that the multiplet at 6 2.17-2.25 for a-sulfonyl

hydrogen of 8 disappears and the presence of a 2 H NMR (38 MHz) singlet at S 2.25 corresponding to a-sulfonyl deuterium.

H n-BuLi. THF _. *78°0—► 25°C A< SOzPh Me3Sj 8 37

Preparation of 1-(Alkyl-substituted)-1-(benzenesulfonyl)*2-{trlmethylsilyl)- cyclopropanea (162).

Alkylation reactions of 160, generated by deprotonation of 6 with n-butyllithium (1.1 equiv), with varied halides were then studied, lodomethane,1 -bromobutane, 1 -iodohexane, benzyl bromide, and allyl bromide are readily displaced (Table 2 ) by 160 in tetrahydrofuran at 2 0 -

25°C to give 1-(benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl)cyclopropanes (162, Equation

20) in 48-78% yields. The stereochemistries of 162 were determined by integration of the 1H

NMR resonances of their trimethylsilyl groups. The E/Z ratios (Table 2) of the 1-(alkyl- substituted)cyclopropanes 163-165 (R = Me, n-C 4 Hg, and n-CeH-o) obtained from reactions of

160 with iodomethane, 1-bromobutane, and 1-iodohexane range from 82:18 to 89:11 and thus are similar to that of protonation of 160. Sulfones 166 and 167 (R = CHgPh and allyl) are obtained as single tranm isomers. As expected, displacements of benzyl bromides and ally! bromide are of relatively low activation energies and therefore more stereospecific than for reactions of usual primary halides.

1. n-Bul_i, THF, -78°C (20)

6 162

RX = Mel, n-C4 HgBr, n-CeH1 3 l, PhCH2 Br, H2 C = C H C H 2Br 38 Table 2. Displacement Reactions of 160* with Alkyl Halides**

Entry Alkyl Halidec Product (R = ) Yield (%)d E/Z Ratios®

1 Mel 163 Me 67 82:18

n-C4 HgBr 2 164 n-C4 H9 48 83:17

n-CeHi3l 3 165 n-CgHi3 52 89:11

4 PhCH2Br 166 CH2Ph 60 1 0 0 : 0

2 5 H ©=CHCH2Br 167 CHZCH = C H 2 78 1 0 0 : 0

®The E/Z ratios of 6 from which 160 was generated range from 76:24 to 80:20. ^For the general synthetic procedure for the displacements, see experimental. C1.5-5.0 equivalents of alkyl halides were used in most reactions. d All yields (%) indicated refer to isolated analytically pure products characterized by 1H and 13C NMR, IR, and HRMS, ®The E/Z ratios are determined by 1H NMR.

Fluoride Ion Reactions of (E)- and (Z)>1-(Benzenesulfonyl)>1-(substituted)-2~ (trlmathylsilyl)cyclopropanes (162).

Study was then directed to reactions of (E)- and (Z)-1-(benzenesulfonyl)-1-(substituted)-

2 -(trimethylsilyl)cyclopropanes (162) with fluoride ion in attempts to prepare 1 -(alkyl- substituted)cyclopropenes (168, Equations 21). The first reactions investigated were (E)- and

(Z)-1-(benzenesulfonyl)-1-(1-hexyl)-2-(trimethylsilyl)cyclopropanes (165) with TBAF ( 2 equiv) in the presence of furan ( 1 0 equiv) or 2 ,3-dimethyl-1,3-butadiene ( 1 0 equiv) as trapping agents in refluxing THF for 0.5-1.0 h. In these experiments, the only product isolated was 1-(1-hexyl)-1-

(benzenesulfonyl)cyclopropane (173) in 75% yield; 1-(hexyl)cyclopropene (168, R = n-C 6 H-|3 ) 39 and/or its Diels Alder adducts with furan or 2P3-dimethy 1*1,3-butadiene were not found. More vigorous conditions for effecting elimination of 165 were then examined. Reactions of 165 with solid TBAF (obtained by removing the THF of a 1.0M solution by rotary evaporation and dried under high vacuum) in diglyme or hexamethylphosphoramide (HMPA) at 25°C, 60°C, or 160°C all give 173. An attempt to eliminate 165 with TBAF at 60°C in the absence of a solvent yields only the desilylated product 173. Cesium fluoride reacts too slowly with 165 to be of value.

TBAF, THF, 65°C (2 1 ) S 02PhMeaSi

S 0 2Ph

169

For desilylation of 162 to give 169 as in Scheme 35, the cyclopropyl carbanion 170 formed initially must pick up hydrogen ion from the reaction environment or survive until aqueous workup. These possibilities were studied by reactions of (E)- and (Z)-1-{benzenesutfonyl)-1- methyl-2-(trimethylsilyl)cyclopropanes (163) with TBAF (2 equiv) in the presence of furan (10 equiv) or 2,3-dimethyl-1,3-butadiene (10 equiv) in refluxing THF for 0.5 h followed by addition of deuterium oxide (10 equiv). The 1H NMR of the 1-(benzenesulfonyl)-1-(methyl)cyclopropane

(171) isolated reveals that no deuterium is incorporated into the product. Thus, it appears that the desilylation intermediate, 2-(benzenesulfonyl)-2-methyl-1-(cyclopropyl)anion (170), picks up hydrogen from the reaction environment. Of concern now is that the benzenesulfonyl group is not an effective leaving group in systems designed to give cyclopropenes. 40 Scheme 35. Protodesilylation of 162

R R H R © Me3 Si S 02Ph * Me3SiF S 0 2Ph S 0 2Ph 169 162 170

In order to determine whether other (l-substituted)silasulfonylcyclopropanes (162) desilylate reductively, the reactions of 164 (R = n-C 4 H9 ), 166 (R = CH2 Ph), and 167 (R = allyl) with TBAF (2 equiv) were investigated in the presence of 2,3-dimethyM ,3-butadiene (10 equiv) in refluxing THF. These experiments gave desilylated products 172, 174, and 175 in 52-70% yields (Table 3); there was no evidence for eliminations to cyclopropenes 168.

Table 3. Fluoride Ion Reactions of 162 to Give Alky(sulfonylOlcyclopropanes 1 6 9 *

Entry Substrate (R = ) Product (R = ) Yields (%)b

1 163 Me 171 Me 45

2 164 n-C4 H9 172 0 -C4 H9 58

3 165 n-CeH1 3 173 />CgH^ 3 75

4 166 CH2Ph 174 CH2Ph 70

5 167 CH 2 C H=C H 2 175 CH 2 C H =C H 2 52

“For general procedure, see experimental. ^Yields refer to isolated unoptimized analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. 41

Reactions of 8 with Epoxides to Give 178 and with Aldehydes and Ketones to Give 186 and Possible Eliminations of 178 and 186 with Fluoride Ion.

3-{Benzenesulfonyl)-6-(trimethylsi!yl)-4-hexen-1-ols (176), products from reactions of 1-

(benzenesulfonyl)-4-(trimethylsilyl)-2-butenes (14) and epoxides and esterification (Scheme 36, see also Scheme 4) have been previously found to be efficiently eliminated to (E)-l-(substituted)-

3,5-hexadien-i-ols (177) by fluoride ion .4 The fact that the eliminations occur in the presence of strong proton donor groups indicate that these elimination reactions are highly concerted.

Although conversions of 1-(alkyl)-1-(benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes (162) to cyclopropenes 168 have now been found unsuccessful, study has been extended to syntheses

Scheme 36. Reactions of 1-(Benzenesulfonyl)-2-(trimethylsilyl)-2>butenes (14) with Epoxides to Give 176 and Eliminations of 176 to 177.

H

1 ^'.THF,-78°C

1 4 2. / \ ; H 3 O ® CH2 CH(OH)R £" ^ r 176

H TBAF, THF. 0°C ^C H 2 CH(OH)R H

177

and possible eliminations of 1 -(benzenesulfonyl)-l-( 2 -hydroxyalkyl)- 2 -

(trimethylsilyl)cyclopropanes (178, Scheme 37).

Reactions of epoxides with 160, obtained from deprotonation of 8 with n-butyllithium

(1 . 1 equiv), take place readily in tetrahydrofuran at 25°C to give cyclopropanols 178 in moderate yields upon acidification with aqueous ammonium chloride. Reactions of 8 with the 42 unsymmetrical epoxides: styrene oxide, propylene oxide, and 1 ,2 -epoxybutane occur regiospecifically t the unhindered methylene positions of the epoxides to give 176. Conditions

Scheme 37. Reactions of 8 with Epoxides to Give 178 and Reactions of 178 with Fluoride Ion

1. n-BuLi, THF.-78°C H sC^Ph

2, /°\^R MeaSi' 'CH2 CH(OH)R

8 178 E 3. H3 C?

,ch 2 ch < o h )r TBAFi t h f

SC^Ph CH2 CH(OH)R 179

were not found for effective reaction of 8 with oxide. The E/Z ratios (Table 4) of 181 and182 (R = Me and Et) obtained from reactions of 8 with propylene oxide and 1,2-epoxy

are 59:41 and 68:32, respectively as determined from the 1H NMR resonances of the

trimethylsilyl protons of the products. Sulfone 180 (R = Ph) is isolated as the single (E)- isomer.

In its reactions with epoxides as with other electrophiles, 160 attacks preferentially or exclusively

with its benzenesulfonyl and its trimethylsilyl groups trmnm to each other. 43

Table 4. Reactions of 8* with Epoxides to Give Cyclopropanols 178^

Entry Epoxidec Product (R = ) Yield (%)d E/Z Ratios®

1 A - ph 180 Ph 40 1 0 0 : 0

2 181 Me 44 59:41

3 / V Et 182 Et 44 68:32

4 o No reaction

*The E/Z ratios of 8 range from 76:24 to 80:20. ^For the general procedure for the condensation of 160 with epoxides, see experimental. c1.5-5.0 equivalents of epoxides were used in most reactions. <*The yields reported refer to isolated analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. ^ h e E/Z ratios are determined by 1H NMR.

As an extension of its behavior with epoxides, reactions of 8 were investigated with aldehydes and ketones to give 1 -(benzenesulfonyl)-l-(t-hydroxyalkyl)- 2 -

(trimethylsilyl)cyclopropanes (183) which might be eliminated by fluoride ion to yield 1-(1- hydroxyalkyl)cyclopropenes (184) as in Scheme 38. Of further relevance is that 2-

(benzenesulfonyl)-2-chloro-1-(trimethylsilyl)-3-alkanols (185) are eliminated by fluoride ion to 2-

(benzenesulfonyl)-1-hexen-3-ols 186 (Scheme 39) and therefore the hydroxyl groups in 185 do not prevent detrimethylsitylbenzenesulfonyl eliminative processes. 44

Scheme 38. Reactions of 8 with Aldehydes and Ketones to Give183 and PossibleEtiminations of 183 to 184

1. n-BuLi, THF, -78 °C

MeaSi 2. RCOR , BF3OEt C(OH)RR‘

+ H ,C(OH)RR' TBAF, THF Me3Si C(OH)RR' 183 Z 184

Scheme 39. Eliminations of Sulfonyl Alcohols 185 to Allylic Alcohols 186

TBAF, THF ,C(OH)RR‘

Cl

185 186

It has been found that the aldehydes, benzaldehyde and 3-methybutyraldehyde, and the ketone, acetone, react with 160 in tetrahydrofuran at 25°C to give cyclopropanols 183 in 48*

55% yields upon acidification with aqueous ammonium chloride (Table 5). Cyclohexanone does not react effectively with 160. The E/Z ratios (Table 5) of cyclopropanols 188 and 189 obtained from reactions of 160 with 3-methylbutanal and acetone as determined from the 1H NMR resonances of their trimethylsilyl groups are 59:41 and 57:41, respectively. Reaction of 160 with benzaldehyde gives 187 as the single (E)- isomer. 45

Table 5. Reactions of 8* with Aldehydes and Ketone to Give Cyclopropanols 1 83^

Entry Carbonyl Compound c Product Yield (%)d E/Z Ratios®

1 PhCHO 187 R = Ph, R' = H 55 1 0 0 : 0

Me2CHCHO 2 188 R = Me 2 CH, R' = H 49 59:41 O 3 189 R = R- = Me 48 57:43 0 1 4 6 No Reaction

®The E/Z ratios of 8 range from 76:24 to 80:20. ^For the general procedure for the condensation of 160 with epoxides, see experimental. c1.5*5.0 equivalents of carbonyl compounds were used in most reactions. ^The yields reported refer to isolated analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. ^ h e E/Z ratios are determined by 1H NMR.

Possible conversions of cyclopropanols 178 and 183 with fluoride ion to give sulfonylcyclopropenes 190 and 191 were then investigated (Equations 22 and 23). Reactions of 180 (R = Ph), 181 (R = Me), and 182 (R = Et) with TBAF (2 equiv) in refluxing THF for 0.5 h in the presence of 2 ,3-dimethyl-1,3-butadiene ( 1 0 equiv) or furan ( 1 0 equiv) afford cyclopropanols

192-194 in 50-78% yields (Table 6 ). In a similar fashion, experiments with 187 (R - Ph, R' = H),

188 (R = Me 2 CH, R’ = H), and 189 (R = R' = Me) with TBAF (2 equiv) in the presence of excess

2,3-dimethyl-1,3-butadiene or furan give desilylated cyclopropanes 195-197 in 52-74% yields

(Table 6 ). All starting materials are consumed and no Diels-Alder adducts are observed. 46

,CH2 CH(OH)R TBAF- THF- 65° C /\ ,S0 2 Ph (22)

Me 3 9 ' SOsPh " ' CH2 CH(OH)R 178 o* — 9 - x 180

,C{OH)RR‘ TBAF’ THF’ 65° C / s o 2 ph ^

Me3a S0 2Ph ^ ^ C(OH)RR‘ 183 o *— y • x ^ 191

Table 6. Fluoride Ion Reactions of 178 and 183 to Give Cyclopropanols 190 and 191

Entry Substrate (R = ) Product (R = ) Yields (%)b

1 180 Ph 192 Ph 55

2 181 Me 193 Me 78

3 182 Et 194 Et 50

4 187 R = Ph, R 1 = H 195 R = Ph, R‘ = H 52

5 188 R = Me 2 CH, R’ = H 196 R = Me 2 CH, R' = H 60

6 189 R = R‘ = Me 197 R = R 1 = Me 74

*For the general procedure, see experimental. ^Yields refer to isolated unoptimized, analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. 47 Preparation and Fluoride Ion Reactions of 1-(Acyl)1-(benzenesulfonyl)-2- (trimethylsllyl)cyclopropanes (198).

The previous efforts in this research to prepare cyclopropenes by elimination reactions of

(E)- and (Z)-1-(benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl)cyclopropanes (9) with fluoride ion have all failed. Desilylations rather than eliminations occur and it appears that the benzenesulfonyl group does not have sufficient leaving group abilities to produce cyclopropenes from benzenesulfonylcyclopropanes. In all of the previous cases studied in this research, however, the substituent in the 1-position is hydrogen or an alkyl group. It is thus possible that the transition states that might allow cyclopropenes to be formed are not sufficiently stabilized by the weak electron-donating non-conjugating 1 -substituents. Further, (E)- and (Z)-1-(acyl)-1-

(benzenesulfonyl)-4-(trimethylsilyl)-2-butenes (198), obtained from reactions of 1-

(benzenesulfonyl)-4-(trimethylsilyl)-2-butenes (14) and acid chlorides (Scheme 40, see also

Scheme 4), have been found to be rapidly eliminated to (E)-1-(substituted)*2,4-pentadien-1-ones

(199) by fluoride ion at 0°C in good yields . 4 Investigation was thus initiated of elimination of 1 -

(benzenesulfonyl)- 2 -(trimethylsilyl)cyclopropanes (8 ) with substituents in the 1 -position which are electron-withdrawing and potentially conjugating.

Scheme 40. Reactions of 1-(Benzenesulfonyl)-2-(trimethylsllyl)-2-butenes (14) with Acid Chlorides to Give 198 and Eliminations of 198 to 199

H H O O ^ 1. o-BuLi, THF,-78°C S0 2 Ph MeaSi Me-jSi 14 2. RCOCI COR 198

H TBAF, THF, 0°C

H

199 48

Study was made of synthesis and possible conjugative silylsulfonyl eliminations of (E)- and (Z)-1-(acyl)-1-(benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes ( 2 0 0 ) by fluoride ion to 1 -

(carbonyl)cyclopropenes (201, Scheme 41). Reactions of acid chlorides with 160, as generated

by deprotonation of 6 with n-butyllithium ( 1 . 1 equiv), are expected to give 2 0 0 efficiently.

Scheme 41. Preparation of 1-(Acyl)-1-(benzenesu1fonyl)-2- (trimethylsilyl)cyclopropanes (200) and Reactions of 200 with Fluoride Ion

1. n-BuLi, THF, -78°C h

Me-jSi 'sC>2 Ph 2. RCOCI MegSi

8 200 E

COR TBAF, THF

200 Z

The acid chlorides: benzoyl chloride, trimethylacetyl chloride, methyl chloroformate and

ethyl chloroformate all react rapidly with 8/n-BuLi in tetrahydrofuran at -78°C to afford 1-(acy1)-1-

(benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes (200) in good yields (64-81%) as summarized

in Table 7. The E/Z ratios (Table 7) of 1 -(carbonyl)cyclopropanes 203-205 (R - CMeg, OMe, and

OEt), as prepared from reactions of 160 with trimethylacetyl chloride, methyl chloroformate and

ethyl chloroformate, respectively, range from 70:30 to 84:16. 1-(Benzenesulfonyl)-1-(benzoyl)-2-

(trimethylsilyl)cyclopropane (202) is isolated from reaction as the single (E)- isomer.

Carbonylations of 160 thus occur to give products in which the benzenesulfonyl groups are

totally or highly trmns (E)- to the 2-trimethylsilyl groups in the cycylopropyl products. 49

Table 7. Reactions of 8/nBuLi* With Acid Chlorides to Give Acyl Derivatives 200

Entry Acid Chloride *7 Product (R = ) Yield (%)d E/Z Ratios®

1 PhCOCI 202 Ph 81 1 0 0 : 0

CICOCMe3 2 203 CMe3 75 70:30

3 CiC02Me 204 OMe 76 80:20

4 CIC02Et 205 OEt 64 84:16

*The E/Z ratios of 8 range from 76:24 to 80:20. ‘’For a general preparative procedure, see experimental. C1.5-5.0 equivalents of acid chlorides were used in most reactions. d Ail yields indicated refer to isolated, analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. ®The E/Z ratios are determined by 1H NMR.

The behaviours of 1-{acyl)-1-(benzenesulfonyl)-2-(trimethylsilyl)cyclopropanes (200) with fluoride ion sources were then explored (Equation 24). Reactions of 202 (R = Ph), 203 (R =

CMe3 ), 204 (R = OMe), and 205 (R = OEt) with TBAF (2 equiv) in refluxing THF for 0.5 h in the presence of 2,3-dimethyl-1,3-butadiene (10 equiv) or furan (10 equiv) were found to give 1-(acyl)-

1 -(benzenesulfonyl)cyctopropanes 207-210 in moderate yields (Table 8). No evidence of any elimination product corresponding to 201 or its Diels-Alder derivatives is obtained; all starting materials were consumed in these reactions. 50

COR TBAF. THF. 65°C 'S0* Ph (24, COR 204 o - X 206

Table 8. Fluoride Ion Reactions of 204 to Give Acyl Products 206

Entry Substrate (R = ) Product (R = ) Yields (%)*>

1 202 Ph 207 Ph 44

2 203 CMe3 208 CMe 3 43

3 204 OMe 209 OMe 60

4 205 OEt 210 OEt 38

aFor the general procedure, see experimental. ^Yields refer to isolated, unoptimized, analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS.

Attempted Elimination Reactions of (Z)-1,2-Bis(benzenesulfonyl)-1 -(trimethyl silyl)cyctopropane (152) and (Z)-1,2*Bls(benzenesulfonyl)cyclopropane (151).

In all of the experiments presently reported, eliminations of (E)- and (Z)-1- benzenesulfonyl)-1 -(substituted)-2-(trimethylsilyl)cyclopropanes (9) to 1-

(substituted)cyclopropenes (10) have failed. The reaction products 211 obtained result from desilylation and then protonation to give 1 -(benzenesulfonyl)- 1 -(substituted)cyclopropanes

(Scheme 42). Review of all of the cyclopropenes whose eliminations were attempted in this 51 Scheme 42. Reactions of 9 with Fluoride Ion to Give 10 or 211

MegSi

211

research reveals that in no case was there a substituent other than hydrogen at C- 2 in the cyclopropane. On the other hand, Z-2-(benzenesulfonyl)~1-(triphenylsilyl)cyclopropanes 212 convert to (triphenylsilyl)cyclopropenes 213 upon reaction with n-butyllithium at 25°C (Scheme

43 ) . 1 2 In the latter systems, the benzenesulfonyl group does leave to yield cyclopropenes 213.

Scheme 43. Reactions of 212 to Give Cyclopropenes 213

H n-BuLi, THF, 25°C

Ph3S SOzPh Ph3St 212 R = Me 213 R = Me (90%) = n-CsHi2 = n-C5H12 (90%) 52 Study was then made of possible eliminations of (Z)-1,2-bis(benzenesulfonyl)-l-

(trimethylsilyl)cyclopropane (152) and (Z)-1,2-bis(benzenesulfonyl)cyclopropane (151) to 1 -

(benzenesulfonyl)cyclopropene (214, Scheme 44). Cyclopropanes 151 and 152 differ from those investigated previously in this work in that there is a substituent other than hydrogen at the carbanionic center generated in the attempted elimination processes.

Scheme 44. Attempted Eliminations of 151 and 152 to Cyclopropane 214

;© n-BuLi

S02Ph SC^Ph PhOzS 214 152 151

Reactions of (Z)-1,2-bis(benzenesulfonyl)-1-(trimethylsilyl)cyclopropane (152) with a variety of fluoride ion sources (TBAF, CsF, and KF) under different experimental conditions (THF, diglyme; temperatures ranging from 25°C to 160°C) fail to yield 1 -

(benzenesulfonyl)cyclopropene (214), the product of elimination. The product obtained, (E)-

1,2-bis(benzenesulfonyl)cyclopropane (217), results from desilylation in 60-80% yields.

Formation of 217 presumably involves generation of Z-anion 215 which epimerizes to E-anion

216 and then undergoes protonation on aqueous work-up (Scheme 45). The product is assigned E-stereochemistry from its 1H NMR spectrum (Figure 4) in which triplets are observed at

5 1.96 and 5 3.19 (J = 7.5 Hz) for the methylene and methine hydrogens, respectively. The methylene hydrogens in 217 are equivalent and the1H NMR of 217 is simpler than that of 151. 53 Scheme 45. Fluoride Ion Reaction of 152

:©

“conditions* 152 215

216 217

3.0 2.0 l.G

Figure 3. 1H NMR of the Upfield Region of (E)-1,2-Bis(benzenesulfonyl)- cyctopropane (217). 54

Synthesis and Trapping of 1-(Benzenesulfonyl)cyclopropene (214).

As summarized in the Introduction. l.l^-trihalo^-ftrimethylsilyOcyclopropanes (218) are eliminated by fluoride ion to afford 1,2-dihalocyclopropenes (219) which are trapped by dienes

220 to give Diels-Alder adducts (221. Scheme 46).7-9 The present study involves synthesis

Scheme 46. Trapping of 1,2-Dihalocyclopropenes 219 with Dienes 220

Y XyA^X TBAF'THF , O

X SiMe3 X X 220 218 219 221

X = Br. Cl X = Br. Cl Y = C, O x = Br, Cl

and reactions of 1-(benzenesulfonyl)cyclopropene (214). Thus, reaction of 1-

(benzenesulfonyl)- 2 -(trimethylsilyl)cyclopropane ( 8 ) with n-butyllithium ( 1 . 1 equiv) and then bromine ( 2 equiv) gives (Z)-1-(benzenesulfonyl)-1-(bromo)-2-(trimethylsilyl)cyclopropane ( 2 2 2 ) as a white solid in 6 8 % yield (Equation 25). The stereochemistry is assigned Z (the bromo and trimethylsilyl groups are c/s) based on NOE studies. Irradiation of the a-silyl proton at 5 2.12 shows a 3% enhancement of the benzenesulfonyl protons. Subsequently, reaction of 222 with

1. n-BuLi, THF, -78 °C (25)

2. Br2

8 222 55 TBAF (2 equiv) in THF at 0°C yields 1-(benzenesulfonyl)cyclopropene (214) which in the presence of 2,3-dimethyl-1,3-butadiene (10 equiv) affords 1-(benzenesulfonyl)-3,4-

(dimethyl)bicyclo[4.1.0.]hept-3-ene (223, Scheme 47) in 6 8 % yield as a viscous colorless oil.

Scheme 47. Reactions of 222 and TBAF in the Presence of 2,3-Dimethy 1-1,3- bu tad ien e

H y A y SQ2Ph TBAF. THF^ /\

Me3Si3Si Br 0°C H.. S . . 0 . 2Ph . . . . .

222 214 223

Similarly, cyclopropane 222 is eliminated by fluoride ion to 214 which is trapped by furan ( 1 0

equiv) to produce (1a, 2p,4p,5a)-2-(benzenesulfonyl)-8-oxatricyclo[3.2.1.0 2 '4]oct-6-ene (224,

Scheme 48) as a colorless oil in 55% yield. The Diels-Alder cycloadduct 224 is obtained as a

Scheme 48. Reaction of 222 and TBAF in the Presence of Furan

O TBAF, THF A

Me3Si Br 0°C H SOzPh

222 214 H single isomer and is assigned exo configuration based on spectroscopic information. 13C NMR

(50 MHz, CDCI3 ) reveals signals for one isomer and mass spectral analysis gives the correct molecular ion (M+). 1H NMR (200 MHz, CDCI 3 ) shows that the bridgehead hydrogens H-| and H5

(Figure 4) at 5 4.77 and 5 4.74 are coupled to the vinyl protons H 7 and He at 5 6.71 and 5 6.63, respectively, and not to the cyclopropyl methine hydrogen H 4 .at 5 2 .1 2 . The assignments of structure 224 are deduced from 1H NMR data in which Halton et al. reported the reaction of 56

Figure 4. 1H NMR (200 MHz) Data lor Exo 224

O

Hi 8 4.77 (d, J = 1.7 Hz) H3a 5 2.43 (dd, J = 3.0, 4.4 Hz)

H3 P 5 1.83 (dd, J = 2.1, 5.2 Hz)

H4 8 2.12 (dd, J = 1 .0 , 4.3 Hz) S 02Ph H5 8 4.74 (d. J = 1.5 Hz)

He 8 6.63 (dd, J = 1.7, 4.0 Hz)

H7 8 6.71 (dd, J = 1.5, 4.0 Hz)

1,2 -dibromocyclopropene (32, Scheme 49) with furan to afford Diels-Alder adducts exo 33 and ernfo 35. 7 The NMR ofaxo hydrogens Hi and H 5 of 224 compare favorably with exo protons

H 1 /H 5 of 33 at 8 4.88. Furthermore, theexo vinyl protons of 224 at 8 6.63 and 8 6.67 are

located more downfield that the encfo vinyl protons of 35 at 8 6.37.

Scheme 49. Reactions of 1,2-Dibromocyclopropene (32) with Furan

exo 33 encfo 35 H3p

8 H, /H 5 8 4.88 (S) H, /Hs 5.10 (d, J = 0.9 Hz))

H ^ 8 2.73 (d, J = 7.3 Hz) H3 a 8 2.27 (d, J = 7.5 Hz)

8 H3 0 8 1.67 (d. J = 7.3 Hz) H3p 1.96 (d, J = 7.5 Hz)

7 8 H6 /H 7 8 6.70 (s) He /H 6.37 (d, J = 0.9 Hz) 57 Alt attempts to isolate 1 -(benzenesulfonyl)cyclopropene {214) under a variety of conditions (THF, -78°C, 0°C, 25°C) led to . The existence of the unstable intermediate 214 was further proven by reaction of 222 with TBAF (2 equiv) in the presence of sodium methoxide (3.5 equiv) to afford (E)-2-methoxy-1-(benzenesulfonyl)cyclopropane (225), a consequence of Michael addition to 214 as shown in Scheme 50. Addition of nucleophiles to

Scheme 50. Reaction of 222 and TBAF in the Presence of Sodium Methoxide

H Br TBAF. THF NaOMe MeO

Me3Si SpgPh NaOMe H SC^Ph

222 214 225

cyclopropenes containing electron withdrawing substituents has been reported previously . ® 4

Cyclopropane 225 is assigned E stereochemistry from the multiplets at 5 3.79-3.86 for the a- methoxy proton in the 1H NMR (200 MHz) and is a single isomer by 13C NMR (50 MHz). The data are compared with similar compounds reported by Padwa; 3,3-dimethyl-2-(trimethylsilyl)-1-(p- toluenesulfonyl)cyclopropene (226) reacts with sodium methoxide to give (E)-3,3-dimethyl-2-

(methoxy)- 1 -(p-toluenesulfonyl)cyclopropane (227, Scheme 51 ) . ® 5 The multiplet at 5 3.79-3.86 of 225 corresponds well to chemical shift at 5 3.62 of 227 in the *H NMR (Figure 5).

Scheme 51. Preparation of 2-Methoxy>3,3>dimethyl-1‘(p* toluenesulfonyl)cyclopropane (227)

NaOMe ^ MeO

226 227 58

Figure 5. 1H NMR of (E)-2-Methoxy-1-(benzenesulfonyl)cyclopropane (225) and (E>- and (Z)-2*Methoxy>3,3>dimathyl<1>(p-toluenaBulfonyl)cyclopropanes (2 2 7 )

5 3.25 (s) 5 2.47-2.56 (m) MeO H

S0 2 Ph

6 3.79-3.86 (m) 225

5 3.25 (s) 5 1.95 (d, J = 3.0 Hz) 6 3.32 (d. J = 6.1 Hz) 5 2.04 (d, J = 6.1 Hz) Me

H SO2 C 7 H7 M eO SO 2 C 7 H 7

6 3.62 (d, J = 3.0 Hz) 6 3.57 (s)

(E)- 227 (Z)-227

The previous attempted eliminations on varied silylsulfonylcyclopropanes with fluoride ion reveal that the benzenesulfonyl group is not a sufficiently good leaving group. To explore further possibilities, a more electron-withdrawing group such as trifluoromethanesulfonyl (SO 2 CF3 ) was

tested as an elimination moiety. 1 -(Benzenesutfonyi)- 2 -(trimethylsilyl)cyclopropane ( 8 ) and n- butyllithium (1.1 equiv) and then trilfuoromethanesulfonic anhydride (1.5 equiv) in THF at -78°C quickly provide (E)- and (Z)-1 -(benzenesulfonyi)-l-(trifluoromethanesulfonyl)- 2 -

(trimethylsilyl)cyclopropanes (228, Equation 26) as a yellow oil in 50% yield with an E/Z ratio of

86:14 as determined from the 1H NMR resonances of the trimethylsilyl peaks. Of note is that reaction of 228 with benzyltrimethylammonium fluoride (2 equiv) in refluxing THF in the presence 59

1. n-BuLi, THF, -78°C (26)

MeaSi S 0 2 Ph 2 ' (CFaSOzte0 8 228

of furan furnishes Diels-Alder adduct, oxatricyclooctene 224, in 50% yield (Equation 27).

Similarly, 228, furan and TBAF in THF at 25°C give 224 in 60% yield (Equation 27). As expected, exo adduct 224 is the only product obtained. The 1H NMR of 224 is identical in all respects to that from the product obtained from reaction of 222 with TBAF in the presence of furan (Scheme 48). It is clear that the triluoromethanesulfonyl moiety is and will be the better leaving group than benzenesulfonyl in eliminations of various 2 -{trimethylsilyl}- 1 -

(sulfonyl)cyclopropanes.

BnMe3 NF, THF. 65°C or TBAF, THF (27)

, 25° C H 228 224

Further Attempted Eliminatlone of 1-(Benzenesulfonyl)-1-(aubatituted)-2-

(trlmethylsilyl)cyclopropanee (9).

Breslow and Crispino report that 1-{benzenesulfonyl)-1,2,3-tri(4-pyridyl)cyclopropane

(229) on reaction with potassium fert-butoxide in THF eliminates benzenesulfinic acid to yield

1,2,3-tri(4-pyridyl)cylopropene (230, Equation 28).63 In the present effort, study was made of 60

KOBu*, THF, 50°C (28) - H 02SPh

229 230

possible base-promoted eliminations of 1 -(benzenesulfonyl)-l-(substituted)- 2 -

(trimethylsilyl)cyclopropanes (9) to 2-(substituted)-1-(trimethylsilyl)cyclopropenes (231, Equation

29). Reaction of 1-

KOBu*, THF (29) HQ2SPh MeaSi S02Ph SiMe3

9 231

yield (Equation 30). The desired product, 1-(trimethylsilyl)-2-(1-hexyl)cyctopropene (232), or its

Diels-Alder adduct was not observed. The difference in the behaviors of 229 and 165 with potassium tert-butoxide is striking. 61

.'iCeHn (30) S 02Ph

166 X 173

232

Attempted Synthesis of 1-($tyryl)vinylcyclopropene (236).

Vinylcyclopropenes 233, potentially useful dienes for syntheses of bicycloheptenes

234 (Equation 31) then became of interest. Synthesis and possible elimination of styrylsulfonylcyclopropane 235 by fluoride ion is summarized in Scheme 52.

(31) < r r 2 233 234

Sulfone 180 is dehydrated to (E ) - 1 -(benzenesulfonyl)-l-(styryl)-2-

(trimethylsilyl)cyclopropane (235) by p-toluenesutfonic acid in refluxing benzene in 77% yield

(Scheme 52). Reaction of 235 with TBAF in refluxing THF however does not yield 1 -(styryl)~ 62 Scheme 52. Synthesis of 1-(Styryl)cyclopropane 235 and Possible Elimination to 1-(Styryi)vinylcyclopropene (236)

pTsOH, PhH, 80°C

Me3Si

180 235

TBAF, THF

Ph 236

cyciopropene (236); 1 -(benzenesulfonyl)- 1 -{styryl)cyclopropane (237, Equation 32) is obtained in 52% yield.

TBAF, THF (32) 65°C Ph Ph 235 237

Further, possible elimination of 235 with potassium ferf-butoxide in THF at 50°C to 1-

(trimethylsilyl)-2-(styryt)cyclopropene (238, Equation 33) results in desilylation to 1-

(benzenesulfonyl)-1-(styryl)cyclopropane (237). Again, nucleophilic attack on the trimethylsilyl group with displacement far outweighs the driving force for elimination to 1 -(styryl)cyclopropene

(238). 63

H ,S02Ph KOBu*, THF, 50°C (33) Me3Si

236 238

The Nature of Quaternary Ammonium Fluorides.

Quaternary ammonium fluorides are widely used as fluoride sources because of their

solubilities. 6 5 ' 6 6 TBAF. an extremely hygroscopic material, is commercially available only as a hydrate (5% water). Upon attempted water removal, TBAF undergoes E2 elimination to bifluoride salt 239 and 1-butene (Equation 34) . 6 7 Water in TBAF strongly diminishes the activity of its fluoride ion. It is likely that reactions of TBAF involve hydrated fluoride ion and/or bifluoride ion.

2 (n-C4 H9)4NF ------► (n-C4 H9 )4 NHF2 + (n-C4 H9)3N + CH 3 CH2CH = CH 2 (34)

239

Christie et at. has prepared anhydrous tetramethylammonium fluoride (Me4 NF) . 6 6 The fluoride however is of limited use in synthesis because of its unsatisfactory solubility. Phosphazenium fluoride 240 has been reported to be an excellent source of “naked" fluoride ion. 6 9 The fluoride

240 has not been used in the present research effort.

© (Me2N)3P = N = P(NM©2)3F©

240 64 In the present investigation, varied 1 -(benzenesulfonyl)-l-(substituted)-2-

(trimethylsilyl)cyclopropanes (9) were not eliminated by fluoride to 1-(substituted)cyclopropenes

(10, Equation 35)). E1cb or stepwise mechanisms presumably take place in which fluoride ion

© (35) MesSi

9 10

effects desilylation of 9 and the cyclopropyl anions 241 generated do not eliminate to cyclopropenes 10 (Scheme 53). It thus appears that the benzenesulfonyl groups do not have sufficient leaving group abilities to yield cyclopropenes 10 and then cyclopropyl anions 241

Scheme 53. E1cb Mechaniem for Formation of Cyclopropane 10

F ©

E 241

H©

S02Ph

protonate to 1 -(benzenesulfonyl)-1-(substituted)cyclopropanes (211). Cyclopropanes 222 (E =

Br) and 228 (E = SO 2 CF 3 ) however are eliminated by fluoride (Scheme 54) to 1- 65 (benzenesulfonyl)cyclopropene (214). E2 (concerted) or even E1 mechanisms may operate in conversions of 222 (E = Br) and 228 (E = SO 2 CF 3 ) to cyclopropene 214 (Scheme 54).

Presumably, the conversions to 214 arise from the excellent leaving group abilities of bromine and trifiuoromethanesulfonyl groups (Scheme 54).

Scheme 54. E2 Mechanism of Formation of Cyclopropene 214

MesSi S 0 2Ph 222 (E = Br) 214

228 (E = SO 2 CF 3 )

As has been noted, commercial TBAF contains as much as 5% water. In the majority of the attempted eliminations of 9 to cyclopropenes 10 in the present research, the TBAF was vacuum-evaporated at 50-60°C overnight before being used in reactions with 9. There was always concern however that there was sufficient water in the TBAF to protonate cyclopropyl anions 241 to cyclopropanes 211 as in Scheme 53 and thus eliminations of 241 to cyclopropenes 10 had been circumvented. A series of experiments was then designed to minimize or possibly eliminate water and /or protons in TBAF solutions. Reactions were thus effected of 1-(benzenesulfonyl)-1-(1-hexyl)-2-(trimethylsilyl)cyclopropane (165) and (E)-1-

(benzenesulfonyl)-1-(styryl)-2-(trimethylsilyl)cyclopropane (235). respectively, at various temperatures (0-65°C) with excess TBAF in THF (Scheme 55) to which n-butyllithium in hexane had been added. Experimentally, n-butyllithium in hexane was syringed into TBAF in THF at

25°C until evolution of gas ceased. Individual solutions of 165 and 235 in THF were then added to the “dried” TBAF/THF/n-BuLi solutions. In all cases (Scheme 55) desilylated cyclopropanes,

173 and 237, respectively, were obtained efficiently in 66-80% yields. Eliminations to 168 and 66 236 did not occur. Of further significance is that reaction of vacuum-dried solid, benzyltrimethylammonium fluoride with 165 did not result in elimination to cyclopropene 168 but cyclopropane 173 is obtained in 76% yield. Although eliminations of 1-(benzenesulfonyl)-1-

(substituted)-2 -(trimethylsilyl)cyclopropanes 9 with ‘'dry" phosphazenium fluoride 240 have yet to be studied. Cyclopropenes 10 are believed not to be formed in the present experiments because of the poor leaving group abilities of the benzenesulfonyl group.

Scheme 55. Reactions of Cyclopropanes 165 and 235 with TBAF Treated with

n-BuLi to Give Cyclopropanes 173 and 237

^CeHi3 TBAF, n-BuLi, THF nCgHt3

S 02Ph S 02Ph

Temperature Yield

0°C 60%

25°C 76% 65°C 72%

H S 0 2Ph TBAF, n-BuLi, THF

Me3Si Ph Ph 236 237

Temperature Yield

25°C 66% 65°C 75% 67

Summary of Results and Further Possible Investigations.

In the present study, an efficient large scale synthesis of 1-(benzenesulfonyl)-2-

(trimethylsilyl)cyclopropane ( 8 ) has been developed. Conversions of 8 to varied 1'

(benzenesulfonyl)-1-(substituted)-2-(trimethylsilyl)cyclopropanes (9) and reactions of 9 with fluoride ion sources give desilylated 1 -(benzenesulfonyl)- 1 -(substituted)cyclopropanes ( 2 1 1 ). 1 -

(Substituted)cyclopropenes (10) are not produced from 9 and fluoride because E1cb losses of the benzenesulfonyl group do not occur. 1-(Benzenesulfonyl)-I-bromo-2-

(trimethylsilyl)cyclopropane ( 2 2 2 ) and 1 -(benzenesulfonyl)- 1 -(trifluoromethanesulfonyl)- 2 -

(trimethylsilyl)cyclopropanes (228) however undergo debenzesulfonyltrimethylsilylation by fluoride ion to yield 1-(benzenesulfonyl)cyclopropene (214), apparently by E2 mechanisms. A practical future direction in this area may be synthesis and elimination of 1 -

(trifluoromethanesulfonyl)- 2 -(trimethylsilyl)cyclopropanes 242 to 1 -(substituted)cyclopropenes

(10).

242 6 8

IV. Experimental Section.

Proton nuclear magnetic resonance spectra were recorded on Bruker AC-200, Bruker

AM-250 or Bruker AC-300 spectrometers and are reported in parts per million on the 5 scale when

CDCI3 is denoted as the solvent with residual CHCI3 at 5 7.26 as an internal reference. The 1 H-

NMR spectra are reported as follows: chemical shifts [multiplicity (s = singlet, 5 = doublet, t = triplet, q = quartet, m = multiplet), coupling constants in Hertz, integration, and interpretation], 1 3 C-NMR spectra were obtained on Bruker AC-200, Bruker AM-250, and Bruker AC-300 spectrometers.

Carbon chemical shifts are reported in parts per million relative to the center line of the CDCI3 triplet (77.0 ppm) and are denoted as "C" (no protons attached), “CH" (one proton attached),

"CHg" (two protons attached) or CH 3 (three protons attached) as determined from the DEPT pulse sequence. Infrared spectra were obtained on a Perkin-Elmer 457 instrument. Mass spectra were recorded on a Kratos MS-30 spectrometer at an ionization energy of 70 eV. Solvents and reagents were dried and purified prior to use when deemed necessary: tetrahydrofuran was predried over potassium hydroxide and distilled from lithium aluminum hydride, diethyl ether was distilled from sodium benzophenone ketyl, and methylene chloride was distilled from calcium hydride. All reactions were conducted under a blanket of argon. Analytical thin-layer chromatography was performed with EM Laboratories 0.25 mm thick precoated silica gel 60F-254 plates. Elemental analyses were performed by Atlantic Microlab, Inc., Norcross, GA. 69

(E)-1-{Phenylthlo)-2-(trlmethylsllyl)ethene (127)3 5

✓ \ H SPh

A solution of thiophenol (8.5 g, 0.077 mol) and (trimethylsilyl)acetylene (10.6 g, 0.108 mol) in dry benzene (200 mL) was irradiated with a 450 W UV lamp lor 10 h. The benzene was removed under reduced pressure, and the resulting brown oil was vacuum distilled at 85-86°C at 0.6 mm

Hg (lit 76-78°C at 0.2 mm Hg) to afford 127 (12.1 g, 54%) as a colorless liquid: 1H NMR (200

MHz, CDCI3 ) 50.11 (s, 9H, SiMe 3 ), 5.94 (5, J - 18.1 Hz, 1 H, vinyl), 6.70 (5, J - 18.1 Hz, 1H, vinyl),

7.29-7.47 (m, 5H, aromatic): 13C NMR (50 MHz, CDCI 3 ) 5 -1.20 (CH3 ), 127.37 (CH). 128.97 (CH),

129.14 (CH), 131.31 (CH), 134.07 (C), 138.43 (CH): IR (neat) 3075, 2950, 2895, 1585, 1545,

1480, 1440, 1305, 1250, 1180, 1090, 1025, 960, 860, 840, 800, 740, 720, 690 cm'1; exact mass calcd for C 1 iH igSSi: m/e 208.0742, found m/e 208.0727.

2*(Benzene8Ulfonyl)-1-(chloro)>1>(trimethylsllyl)ethane (135).3®

Me3 Si— CH— CH2 — SOzPh Cl

A solution of trimethyl(vinyl)silane (9.0 g, 0.090 mol), benzenesulfonyl chloride (16.0 g, 0.090 mol) and cuprous chloride (200 mg) in dry acetonitrile (10 mL) was heated for 22 h at 130°C in a sealed tube. The brown mixture was cooled, diluted with methylene chloride (50 mL), washed with dilute hydrochloric acid ( 2 x 50 mL) and aqueous Na2 EDTA ( 2 x 50 mL), dried (MgSC>4 ), 70 filtered, and concentrated in vacuo to afford a pale yellow oil which was vacuum distilled at 156-

157°C at 0.8 mm Hg to yield 135 (17.0 g, 6 8 %) as a colorless liquid.: 1H NMR (250 MHz, CDCI3 )

5 0.08 (S, 9H, SiM« 3 ), 3.30-3.67 (m, 3H, CH, CH2 ), 7.49-7.72 (m, 3H, aromatic), 7.90-8.02 (m, 2H.

aromatic): 13C NMR (62 MHz, CD 3 CI) 8 -3.97 (CH 3 ), 40.94 (CH 2 ), 60.14 (CH), 128.33 (CH),

129.15 (CH), 133.81 (CH), 139.61 (C); IR (neat) 3065, 2960, 1585, 1480, 1385, 1325, 1290,

1250, 1140, 1085, 1025, 1000, 890, 845, 790, 735, 690, 545 cm'1; exact mass calcd for

CsH^SiCI (M+ - S0 2 Ph): m/e 137.0367, found m/e 137.0371.

(E)-1-(Benzene8ulfonyl)-2-(trlmethyls(lyl)ethene (128).36

Me3 Siv H \ / H SOzPh

A yellow white suspension of 135 (14.6 g, 0.053 mol) and triethylamine (40 mL) in dry benzene

(300 mL) was stirred for 40 h at room temperature under argon. The mixture was washed with dilute hydrochloric acid (2 x 150 mL), saturated aqueous sodium bicarbonate (100 mL), and brine

(100 ml), dried (MgS0 4 ), filtered, and concentrated in vacuo to a pale yellow oil which was recrystallized from to yield 128 (9.2 g, 72%) as a colorless solid: mp 58-60 C° (60-

62°C); 1H NMR (200 MHz, COCI3 ) 8 0.09 (S, 9H, SiMe 3 ), 6.61 (8 , 17.9H, 1 H, vinyl), 7.20 ( 8 .

17.9H, 1H, vinyl), 7.44-7.61 (m, 3H, aromatic), 7.61-7.85 (m, 2H, aromatic); 13C NMR (50 MHz,

CDCI3 ) 8 -2.23 (CH3 ), 127.68 (CH), 129.10 (CH). 133.28 (CH), 139.51 (C). 141.46 (CH), 145.29

(CH); IR (KBr) 3065, 3030, 2960, 1585, 1480, 1445, 1320, 1250, 1165, 1150, 1085, 1070, 845,

795, 685, 565 cm'1; exact mass calcd for C 1 0 H 1 3 SO2 S1 (M+ - CH3 ): m/e 225.0405, found m/e

225.0415. 71 i-(p-Tolyl)ethynyl-2-(trlmethylsllyl)sulfone (137).45

Me3Si CEC—S0 2 C 7 H7

p - Toluenesulfonyl chloride (5.0 g, 0.031 mol) was added to a slurry of aluminum chloride (4.1 g, 0.031 mol) in dry methylene chloride (30 mL) under argon. The mixture was quickly filtered through glass wool into an addition funnel and added over 1 h to a solution of bis(trimethylsilyl)acetylene (5.0 g, 0.029 mol) in dry methylene chloride (30 mL) at 0®C. The brown mixture was then stirred 10 h and added to a slurry of dilute HCI and ice. The layers were separated and the organic layer was washed with water (2 x 100 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to a brown residue which was recrystallized from petroleum ether to yield

137 (3.1 g. 43%) as tan crystals: mp 77-78°C (lit 81-82°C); 1H NMR (200 MHz, CDCI 3 ) 6 0.22 (s,

9H, SiMe 3 ), 2.47 (s, 3H, CH3 ), 7.37 (8 . J - 8.3 Hz, 2H, aromatic), 7.88 ( 8 , J - 8.3 Hz, 2H, aromatic):

13C NMR (50 MHz, CDCI3 ) 8-1.20 (CH 3 ), 21.70 (CH3 ), 98.35 (C), 101.34 (C). 127.54 (CH), 129.91 (CH), 138.45 (C), 145.37 (C): IR (KBr) 2965, 2125, 1595,1400, 1335, 1300, 1260, 1165,

1085, 855, 770 cm '1 ; exact mass calcd for C i 2 H i 6 0 2 SSi: m/e 252.0640, found m/e 252.0643.

(Z)-1-(p-Toluenesulfonyl)-2-(trlmethytsllyl)ethene (138).36

Me3 Si/ NS 0 2 C7 H7

A mixture of 137 (1.1g, 4.36 mmol) and 5% palladium on barium sulfate (100 mg) in dry methanol

(30 mL) was stirred under a balloon of hydrogen for 6 h. The catalyst was filtered over Celite and the filtrate was concentrated in vacuo to a yellow oil which was chromatographed (silica gel; methylene chloride: petroleum ether, 1:1) to afford 138 (892 mg, 81%) as a yellow oil: 1H NMR

(200 MHz, CDCI3 ) 8 0.31 (s, 9H, SiMe 3 ), 2.41 (S, 3H, CH3 ). 6.52 (8 , J - 13.9 Hz, 1H, vinyl), 6.81

(8 , J - 13.9 Hz, 1H, vinyl), 7.31 ( 8 . J - 8.0 Hz, 2H. aromatic). 7.73 ( 8 , J - 8.0 Hz, 2H, aromatic); 13C

NMR (50 MHz, CDCI3 ) 8 0.10 (CH3 ), 21.51 (CH3 ), 127.58 (CH), 129.81 (CH), 137.20 (C), 143.39 72 (CH), 144.35 (C). 146.37 (CH); IR (neat) 2955, 2900, 1595, 1495, 1445, 1405, 1315, 1250,

1145, 1085, 1020, 850, 790, 750, 700, 650 cm-1; exact mass calcd for C i 2 H ie 0 2 SSi: m/e 254.0797, found m/e 254.0770.

p-Tosyimethylenetrlphenylphosphorane (142).50

H,C

n-Butyllithium (6.0 mL, 12.6 mmol, 2.1 M In hexanes) was syringed into a suspension of methylenetriphenylphosphonium bromide (4.1g, 11.5 mmol) in dry THF (40 mL) under argon at room temperature. After 2 h, p - toluenesulfonyl fluoride (1.0 g, 5.74 mmol) in dry THF (10 mL) was added dropwise to the dark orange solution. The mixture was stirred 1 h, diluted with water

(100 mL), extracted with methylene chloride (3x50 mL), and the combined organic extracts were washed with brine (100 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to give an oity white-yellow solid which was recrystallized from methylene chloride-hexanes to yield 142 (1.2 g,

50%) as a white solid: mp 177-179°C; 1H NMR (200 MHz, CDCI3 ) 5 2.29 (s, 3H, CH 3 ), 5.26 (s.

1 H, CH), 6.97 (5, J - 8.0 Hz, 2H, aromatic), 7.28-7.69 (m. 17H, aromatic); 13C NMR (50 MHz,

CDCI3 ) 6 21.11 (CH3 ), 124.76 (CH). 125.93 (CH), 127.78 (CH), 128.41 (CH), 128.44 (CH).

128.70 (CH), 131.99 (CH), 132.05 (CH), 133.00 (CH), 133.21 (CH). 139.64 (C), 146.82 (C); IR

(KBr) 3055, 1600, 1480, 1435, 1400. 1265, 1215, 1125, 1080, 970, 810, 750, 715, 695, 660 cm*1; exact mass calcd for C 2 6 H2 3 O 2 PS: m/e 430.1156, found m/e 430.1115. 73

p-Toluenesulfonyldiazomethane (141).50

H,C

A solution of 142 (400 mg. 0.929 mmol) in dry methylene chloride (5.0 mL) was added slowly

over 2 h to a solution of p - toluenesulfonyl azide ( 2 2 0 mg, 1 . 1 1 mmol) in dry methylene chloride

(5.0 mL) at room temperature. The mixture was stirred 2h and then concentrated in vacuo to a

brown oil which was chromatographed (alumina; methylene chloride) to afford 141 (125 mg. 69%)

as a yellow oil: 1H NMR (200 MHz. CDCI 3 ) 6 2.41 (s, 3H, CH3 ), 5.30 (s, 1H. CH). 7.31 (5, J - 8.0

Hz. 2H, aromatic). 7.72 (5. J«8.0Hz, 2H. aromatic); 1 3c NMR (50 MHz, CDCI 3 ) 5 21.40 (CH3),

57.80 (CH), 126.09 (CH), 127.66 (CH), 129.71 (CH). 144.19 (C); IR (neat) 3060, 2995. 2930,

2105, 1600, 1485, 1350, 1330, 1150, 1090, 1005, 915, 815, 780, 665 cm'1; exact mass calcd for CQHQN2 O 2 S: m/e 196.0307, found m/e 196.0303.

(E)- and (Z)-l-(p -Toluene8ulfonyl)-2-(trlmethylslly1)cyclopropanes (143).

A solution of p -toluenesulfonyldiazomelhane (141, 206 mg, 1.05 mmol) in dry methylene chloride (5.0 mL) was added over 1 h to a refluxing solution of vinyltrimethylsilane (1.05 g, 10.5 mmol) and rhodium acetate dimer (spatula tip) in dry methylene chloride (10 mL). The mixture was 74 then concentrated in vacuo to a yellow oil which was chromatographed (alumina; ethyl

acetate petroleum ether, 1:5) to afford 1 4 3 (57 mg, 21%) a6 a light yelow oil: 1H NMR (200 MHz,

COCO) 5-0.11 (s,9H, SiMe 3 , E),0.23 (s, 9H, SiMe 3 , Z), 0.62-0.72 (m, 1H. cyclopropyl H), 0.76-

0.91 (m, 1 H, cyclopropyl H), 1.05-1.32 (m, 1 H, CHSiMe3 , E), 1.46-1.55 (m, 1H, CHSiMe3 , Z),

2.23-2.38 (m, 1H, CHSQ 2 C7 H7 . E), 2.44 (s, 3H, ArCH3 ), 2.48-2.64 (m, 1H, CHSQ 2 C7 H7 , Z).

7.33 (5, J - 8.0 Hz, 2H, aromatic). 7.78 ( 8 . J - 8.0 Hz, 2H, aromatic);13C NMR (50 MHz, CDCfc) 8

-2.94 (CH3. E). -0-26 (CH 3 , Z), 6.29 (CH 2 , E), 8.82 (CH 2 , Z), 9.24 (CH, E), 10.73 (CH, Z), 21.60

(CH3 ), 36.81 (C. E), 39.58 (C, Z), 127.47 (CH, E), 127.56 (CH. Z), 129.34 (CH, E), 129.72 (CH,Z),

129.80 (CH, E). 138.08 (C, Z), 143.93 (C. E); IR (neat) 2955, 1595, 1355, 1300, 1245, 1180,

1150, 1085, 1010, 920, 840, 735, 665 cm'1; exact mass calcd for C i 3 H2 0 O2 SSi: m/e

268.0929, found m/e 268.0941.

Cis-1-propyl-2-(trlmethylsllyl)oxlrane(l44).5 1

sec-Butyllithium (19.5 mL, 21.4 mmol, 1.1 M in ) was syringed into a solution of

(chloromethyl)trimethylsilane (2.5 g, 20.4 mmol) in dry THF (20 mL) at -76°C under argon. Aler 5

min, TMEDA (2.5 g, 21.4 mmol) was added dropwise, and the pale yellow suspension was

warmed to -55°C over 30 min before a solution of butyraldehyde (1.18 g, 16.3 mmol) in dry THF

(15 mL) was added slowly. The mixture was then stirred 8 h at room lemperature, quenched with

0.5 N HCI (60 mL) and extracted with methylene chloride (3 x 60 mL). The combined organic

extracts were washed with brine ( 2 x 50 mL), dried (MgS 0 4 ), filtered, and concentrated in vacuo

to a yellow liquid which was vacuum-distilled at 45-47°C at 4.0 mm Hg to afford 14 4 (1.35 g, 52%) 75

as a colorless liquid: 1H NMR (200 MHz, CDCI3 ) 5 0.08 (s, 9H. SiMe 3 ), 0.77-0.97 (m, 3H, CH3),

1.31-1.63 (m, 4H, CH2). 2.13-2.32 (m, 1H, CHO), 3.01-3.10

CDCI3 ) 5 -1.85 (CH 3 ), 13.93 (CH 3 ), 20.27 (CH2), 33.53 (CH2), 50.40 (CH). 57.39 (CH); IR (neat)

2960, 1465, 1420,1250, 840, 755 cm*1; exact mass calcd lor CgH-isOSi: m/e 158.1127, found m/e 158.1132.

(2R,3R)-l-(Benzenesulfonyl)-3-(hydroxy)-2(trlmethyfsllyl)hexane (145).

OH

PhSO. SiMe

n -Butyllithium (2.85 mL, 5.97 mmol, 2.1 M In hexanes) was syringed In slowly to a solution of methyl phenyl sulfone (890 mg, 5.68 mmol) in dry THF (20 mL) at -20°C under argon. After the yellow suspension had been stirred 0.5 h, 144 (450 mg, 2.84 mmol) was added dropwise, followed by boron trifluoride etherate (806 mg, 5.68 mmol) during which a colorless solution appeared. After 5 min, the mixture was quenched with saturated aqueous sodium bicarbonate

(10 mL) and extracted with methylene chloride (3 x 20 mL). The combined organic extracts were washed with brine (2 x 1 0 mL), dried (MgS0 4 ), filtered, and ooncentrated in vacuo to a colorless oil which was chromatographed (silica gel; ethyl acetate:petroleum ether, 1:3) to yield 145 (677 mg, 76%) as a colorless oil: 1H NMR (200 MHz, CDO 3 ) 6 -0.02 (s, 9H, SiMe3), 0.87 (t, J - 6 . 6 Hz.

3H, CH3), 1.30-1.50 (m, 5H, CH2, CHSiMe3), 2.53 (5, J - 8.1 Hz, 1H, OH). 2.97 (dd. J - 2.9,14.5

Hz, 1 H, PhS0 2 CHH), 3.44 (dd, J - 7.7, 14.5 Hz. 1H, PhS0 2 CHH), 3.68 (m. 1 H, CHOH), 7.47-

7.65 (m, 3H, aromatic). 7.84-7.88 (m, 2 H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 -2.35 (CH3 ),

13.81 (CH 3 ), 19.10 (CH2), 27.19 (CH), 40.64 (CH2), 53.97 (CH2), 70.28 (CH). 127.82 (CH), 76

129.19 (CH), 133.56 (CH), 139.53 (C); IR (neat) 3525, 2960, 1450. 1305, 1250, 1150, 1085,

1025, 840, 790, 690 cm'1; exact mass calcd for C i 5 H2 5 0 2 SSi (M+ - OH): m/B 297.1344, found

m/e 297.1319.

(E)-l-(Benzenesulfonyl)>2-hexene (148).

PhSO-

A solution of 145 (144 mg, 0.458 mmol), p-toluenesulfonyl chloride (105 mg, 0.550 mmol),

triethylamine (232 mg, 2.29 mmol), and DMAP (62 mg, 0.504 mmol) In dry methylene chloride (2.0

mL) was stirred 10 h at room temperature. After the mixture has quenched with 0.5 N HCI (20 mL)

and extracted with methylene chloride (3 x 10 mL). The combined organic extracts were washed

with brine (20 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo. The brown oil was

chromatographed (silica gel; ethyl acetate:petroleum ether, 15) to give 148 (82 mg, 80%) as a

colorless oil: 1H NMR (200 MHz, CDCI 3 ) 8 0.80 (t, J - 6 . 1 Hz, 3H, CH3 ), 1.16-1.32 (m, 2H, CH2 ),

1.90-2.01 (m, 2H, CH 2 ), 3.70 (5, J - 7.0 Hz, 2H, PhS02CH2), 5.26-5.52 (m, 2H, vinyl H), 7.45-

7.61 (m, 3H, aromatic), 7.78-7.85 (m, 2 H. aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 13.33 (CH3 ),

21.66 (CH 2 ), 52.45 (CH 2 ), 59.94 (CH 2 ). 115.84 (CH), 128.30 (CH), 128.84 (CH). 133.49 (CH),

138.14 (C), 141.49 (CH); IR (neat) 3040, 3015, 2960, 2930, 1585, 1450, 1370, 1320, 1300,

1240, 1175, 965, 750 cm '1; exact mass calcd for C 6 H 1 1 (M+ - H): m/e 223.0793, found m/e

223.0797. 77

Chloromethyl Phenyl Sulfide (149).56

PhSCH2CI

Sulfuryl chloride (16.2 g, 0.120 mol) in dry methylene chloride (30 mL) was added over 1h to a refluxing solution of thioanisole (15.0 g, 0.120 mol) in dry methylene chloride (100 mL). The mixture was refluxed for 3 h, cooled, and concentrated in vacuo to a yellow liquid which was vacuum-distilled at 75-77®C at 3.0 mm Hg to afford 149 (17.1 g, 90%) as a yellow liquid: 1H NMR

(200 MHz, CDCI3 ) 6 4.99 (s, 2 H, CH2 ), 7.37-7.54 (m, 3H, aromatic), 7.58-7.62 (m, 2H, aromatic);

1 3C NMR (50 MHz, CDCI3 ) 5 50.90 (CH 2 ), 127.82 (CH), 129.12 (CH), 130.70 (CH), 133.14 (C); IR

(neat) 3060, 1580, 1480, 1440. 1395, 1225. 1090, 1025, 850, 740, 690, 645 cm*1; exact mass calcd for C 7 H7 CIS: m/e 157.9957, found m/e 157.9951.

Phenyl Vinyl Sulfide (130).5 5

■ ^ ^ S P h

Thiophenol (27.8 g, 0.25 mol) was added dropwlse to sodium ethoxide prepared from sodium

(5.8 g, 0.25 mol) and absolute ethanol (100 mL). The pale yellow mixture was then added over ih to a mechanically stirred solution of 1,2-dibromoethane (56.3 g, 0.30 mol) and ethanol (5.0 mL).

After 0.5 h, ethanolic sodium ethoxide prepared from sodium metal (12.7 g, 0.55 mol) and absolute ethanol (200 mL) was added over 1 h to the milky white suspension. The mixture was

then refluxed 1 2 h, cooled, diluted with benzene (400 mL), washed with water (3 x 100 mL) and brine (100 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo. The pale yellow oil was vacuum-distilled at 45-50°C at 2.0 mm Hg to give 130 (16.1 g, 48%) as a colorless liquid: 1H

NMR (200 MHz, COCI3 ) 5 5.34 (superimposed dd, J -6 .5 ,16.4 Hz, 2H, terminal vinyl), 6.55 (dd. J

- 9.5, 16.7 Hz, 1H, olefin), 7.26-7.38 (m, 5H, aromatic): 1 3c NMR (50 MHz, CDCI 3 ) 5 115.29

(CH 2 ). 126.94 (CH), 128.98 (CH), 130.31 (CH), 131.76 (CH), 134.14 (C); IR (neat) 3060, 1585,

1480, 1375, 1265, 1095, 1025, 955, 900, 745, 690 cm-1; exact mass calcd for C s ^ S : m/e

136.0347, found m/e 136.0331.

(Z)-1,2-Bls(phenylthlo)cyclopropane (ISO ) . 5 7

PhS SPh

Benzyltriethylammonium chloride (6.4 g, 0.028 mol) was added to a biphasic mixture of 50%

aqueous sodium hydroxide (120 mL) and phenyl vinyl sulfide (18.9 g, 0.139 mol) and

chloromethyl phenyl sulfide (24.3 g, 0.153 mol) in methylene chloride (150 mL). The mixture was

mechanically stirred for 18 h, diluted with water (300 mL) and extracted with diethyf ether (3 x 150

mL). The combined organic extracts were washed with water (2 x 150 mL) and brine (150 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to give 150 (35.0 g, 97%) as a yellow oil

which was spectroscopically pure and used without purification in the next step: 1 H NMR (200

MHz, CDCI3 ) 5 1.01 (q, J-5.8 Hz, 1H, cyclopropyl H), 1.74-1.82 (m, 2 H, cyclopropyl H). 2.77 (q,

J-5.8 H. 2H, CHSPh), 7.18-7.48 (m, 1 0 H, aromatic): 15C NMR (50 MHz, CDCI 3 ) 8 16.12 (CH2 ).

22.32 (CH), 125.30 (CH), 127.66 (CH). 128.56 (CH), 137.10 (C); IR (neat) 3060, 1585, 1480,

1440, 1275, 1090, 1025, 910, 735, 690 cm’1; exact mass calcd for C 1 5 H 1 4 S 2 : m/e 258.0537, found m/e 258.0522. 79

(Z)-1,2-Bis(benzenesulfonyl)cyclopropane (151).57

Aqueous hydrogen peroxide (30%, 130 mL, 1.16 mol) was added dropwise to a cold (0°C)

solution of 150 (25.0 g, 0.097 mol) in glacial acetic acid (250 mL). The mixture was refluxed 1 2 h, cooled, and poured into water (500 mL). A white solid precipitated which was vacuum-filtered and recrystallized from ethanol to afford 151 (25.3 g, 81%) as a white solid: mp 152-154° C (165-

166°C); 1H NMR ( 2 0 0 MHz, CDO 3 ) 5 1.70-1.82 (m, 1 H, cyclopropyl H), 2.48 (q, J=6.2 Hz, 1 H, cycopropyl H), 2.93 (t, J=7.7 Hz, 2H, CHSC> 2 Ph), 7.53-7.72 (m. 6 H, aromatic). 8.02 ( 8 , J = 7.0 Hz.

4H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 6 12.97 (CH 2 ), 43.31 (CH), 128.24 (CH), 129.18

(CH133.92, CH), 140.45 (C); IR (KBr) 3035, 1640, 1445, 1400, 1330, 1310, 1160, 1085, 890,

735, 690, 635 cm'1; exact mass calcd for C 1 5 H 1 4 O4 S2 : m/e 322.0334, found m/e 322.0347.

(Z)-1,2-Bi8(benzenesulfonyl)-1-(trlmethylsilyl)cyclopropane (152).

SiMe<

n -Butyllithium (6.2 mL, 10.9 mmol, 1.75 M in hexanes) was syringed into a solution of 151 (3.2 g,

9.93 mmol) in dry THF (120 mL) at -78°C under argon. After 30 min, chlorotrimethytsilane (1 . 6 g, 80 14.9 mmol) was added dropwise to the brown solution. The mixture was stirred 15 min, diluted

with diethyl ether (200 mL), washed with water (200 mL) and brine (200 mL), dried (M0 SO4 ),

filtered, and concentrated in vacuo. The resulting yellow oil was chromatographed (silica gel; ethyl

acetate petroleum ether, 1 :1 ) to give 1 5 2 (2.1 g, 54%) as a tan-white solid: mp 113-115°C; 1H

NMR (200 MHz, CDCfc) 5 0.19 (S, 9H, SiM 6 3 ), 1 75 (dd, J - 3.6, 5.7 Hz, 1H, cyclopropyl CH), 2.06

(dd. J - 3.6, 5.6 Hz. 1H, cyclopropyl CH), 3.57 (dd, J - 2.7, 6 . 6 Hz. IH.CHSCfePh), 7.56-7.72 (m,

3H, aromatic), 7.94-7.99 (m, 2H, aromatic); 13C NMR (50 MHz, CDC|3)60.57 (CH 3 ), 14.92 (CH 2 ),

39.28 (C), 47.11 (CH), 127.77 (CH), 127.86 (CH), 129.22 (CH), 129.52 (CH), 133.76 (CH),

134.08 (CH), 140.23 (C), 140.43 (C); IR (KBr) 3070. 3020, 2900, 1585, 1480, 1445, 1410,1290,

1250. 1200, 1150, 1090, 1025, 1000, 940, 865, 840 cm*1; exact mass calcd lor

C igH 2 2 0 4 S2 Si: m/e 394.0729, found m/e 394.0703. Anal. Calcd for C isH 2 2 0 4 S 2 Si: C,

54.79; H, 5.62. Found: C, 54.89; H, 5.57.

(E)- and (Z)*1*(Benzenesulfonyl)-2*(trlmethylsilyl)cyclopropanes(8).

Sodium amalgam (13.6 g, 35.5 mmol, 6 %) was added in portions to a suspension of 1 5 2 (3.5 g,

8.87 mmol) and sodium dihydrogen phosphate monohydrate (4.9 g, 35.5 mmol) in methanol (200 mL) at room temperature. The mixture was mechanically stirred 1h, diluted with water (200 mL) and extracted with methylene chloride (3 x 200 mL). The combined organic extracts were washed with brine (200 mL), dried (MgSOt4 ). filtered, and concentrated in vacuo to a colorless oil which was chromatographed (silica gel; ethyl acetate:petroleum ether, 1:5) to affordB (1.52 g, 67%) as a 81 colorless oil: 1H NMR (200 MHz, CDCfc) 8 -0.16 (s, 9H, SiMe 3 , E), 0.19 (s, 9H. SiMe 3 , Z), 0.56-

0.70 (m, 1H, cyclopropyl H), 0.79-0.92 (m, 1H, cyclopropyl H), 1.44-1.53 (m, 1 H,CHSiMe3 ), 2.17-

2.25 (m, 1 H, CHS 0 2 Ph), 7.45-7.60 (m, 3H, aromatic), 7.61-7.86 (m. 2H, aromatic); 13C NMR (50

MHz, CDCI3 ) 8-3.14 (CH 3 , E), -0.43 (CH3 , Z), 6.33 (CHa, E), 9.13 (CH, Z), 10.12 (CH. E), 10.64

(CH, Z), 36.46 (C. E). 39.21 (C, Z), 127.18 (CH. E), 127.91 (CH. Z). 128.74 (CH. E). 128.93 (CH,

E), 132.93 (CH, Z). 133.05 (CH.E). 140.73 (C); IR (neat) 2955, 1585, 1445, 1300, 1250, 1150,

1090, 900, 840, 730, 690cm'1; exact mass calcd for C 1 2 H 1 8 O 2 SSL m/e 254.0797, found m/e

254.0795. Anal. Calcd tor C i 2 H is 0 2 SSi: C, 56.65; H, 7.13. Found: C, 56.84; H, 7.15.

Fluoride Ion Reaction of (E)- and (Z)<1-(Benzenesulfonyl)*2>

(trlmethylsilyl)cyclopropanes(8).

A;- SCfePh

A mixture of 8 (101 mg, 0.397 mmol) and TBAF (0.80 mL, 0.80 mmol, 1.0 M in THF) in the presence of 1,3-diphenylisobenzofuran (107 mg, 0.397 mmol) in dry THF (10 mL) was stirred 24 h, diluted with diethyl ether (20 mL), washed with water (20 mL) and brine (20 mL), dried (MgS0 t4 ), filtered, and concentrated in vacuo to a brown oil which was chromatographed (silica gel; ethyl acetate; petroleum ether, 1 :5) to give 8 8 (44 mg, 60%) as a colorless oil: 1H NMR (200 MHz,

COCI3 ) 8 1.01-1.08 (m, 2H. cyclopropyl H), 1.25-1.40 (m, 2 H, cyclopropyl H), 2.40-2.50 (m, 1 H,

CHSQ 2 Ph), 7.51-7.69 (m, 3H, aromatic), 7.88-7.92 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 )

8 5.92 (CH 2 ), 32.87 (CH), 127.51 (CH). 129.17 (CH), 133.30 (CH), 140.67 (C); IR (neat) 3060,

2960. 1585, 1445, 1315, 1290, 1145, 1090, 885, 760,730, 690 cm*1; exact mass calcd for

C9 H 1 0 O2 S m/e 182.0402, found m/e 182.0404. 82

General Procedure A for Reactions of 160 With Electrophlles:!

(Benzenesulfonyl)-1-(deuterio)-2-(trimethylsilyl)cyclopropanes(l6l).

n -Butyllithium (0.55 mL. 0.497 mmol, 0.90 M in hexanes) was syringed into a solution of 8 (115

mg, 0.452 mmol) in dry THF (10 mL) at -78° C under argon. After 15 min, deuterium oxide (45 mg,

2.26 mmol) was added to the bright orange solution. The mixture was then stirred 30 min at room temperature, diluted with diethyl ether (20 mL), washed with water (20 mL) and brine (20 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo. The yellow oil was chromatographed (silica gel; ethyl acetate:petroleum ether, 1:5) to afford 161 as a colorless oil (95 mg, 82%): 1H NMR

(200 MHz, CDCfc) 8 -0.14 (s, 9H, SiMe 3 . E). 0.43 (S. 9H. SiMe 3 , Z), 0.67 (dd, J - 2.9, 11.2 Hz, 1 H,

CHSiMes), 0.86 (dd, J - 4.4, 8.3 Hz, 1 H, cyclopropyl H), 1.51 (dd. J - 4.3, 11.2 Hz, 1H.

cyclopropyl H), 7.49-7.62 (m, 3H, aromatic), 7.84-7.90 (m, 2H, aromatic); 1 3CNMR MHz,

CDCfc) 8 -3.01 (CH3 , E), 1.34 (CH3 , Z), 5.93 (CH), 6.24 (CFfe, E), 9.18 (Ct-fe, Z), 37.88 (C),

125.84 (CH. Z), 127.47 (CH, E). 128.27 (CH, E). 129.10 (CH. Z), 129.21 (CH, E), 133.18 (CH. Z).

140.87 (C,E), 141.95 (C, Z); IR (neat) 2955,1450, 1310, 1250, 1150, 1090, 840, 735, 690 cm'

1 ; exact mass calcd forCi 2 H 1 7D02SSi: m/e255.0859, found m/e 255.0852. 83 1-(Benzenesullonyl)-i-(methyl)-2-{trimethylsllyl)cylopropanes(163).

Me

SOfePh

Following general procedure A with 8 (156 mg, 0.613 mmol), n-butyllithium (0.75 mL, 0.674 mmol, 0.90 M in hexanes), and dimethyl sulfate (116 mg, 0.920 mmol) for 15 min gave 1 6 3 as a yellow oil (111 mg, 67%): 1H NMR (200 MHz. CDCI 3 ) 6 -0.01 (s, 9H, SiMe 3 , E), 0.42 (s, 9H,

SiMe3 , Z), 0.77 (dd, J - 4.3, 8.5 Hz, 1 H, CHSiMe3 ), 0.89 (dd, J - 2.5, 11.0 Hz, cyclopropyl H),

1.34 (s, 3H, CH3 ), 1.75 (dd, J - 4.1, 11.6 Hz, 1 H, cyclopropyl H), 7.50-7.62 (m, 3H, aromatic),

7.83-7.86 (m. 2 H, aromatic): 13C NMR (50 MHz, CDCI 3 ) 8 -1.03 (CH3 , E), 1.48 (CH 3 , Z), 10.86

(CH3 , E), 13.10 (CH3 , Z), 15.82 (CH, Z), 16.00 (CH, E), 18.29 (CH 2 , Z), 20.03 (CH2 , E). 37.44 (C,

Z), 41.44 (C, E), 128.66 (CH, Z), 128.75 (CH, E), 129.42 (CH, Z). 130.39 (CH, E), 132.63 (CH, E),

133.38 (CH, Z), 136.50 (C, E), 138.44 (C, Z); IR (neat) 2955, 2895, 1595, 1445, 1305, 1250,

1190, 1145, 1075, 840, 790, 760, 725, 690, 6405 cm'1; Exact mass calcd for C 1 3 H 2 0 O2 SS1: m/e 268.0953, found m/e 268.0950. Anal. Calcd for C i 3 H2 0 O 2 SSi: C, 58.16; H, 7.51. Found:

C, 58.24; H, 7.58.

1-(Banzenesulfonyl)-1-(l-butyl)-2-(trlmethylsilyl)cyclopropanes(164).

SCfePh 84

General procedure A using 8 (181 mg, 0.711 mmol), n -butyllithium (0.60 mL, 0.783 mmol, 1.30

M in hexanes), and 1 -bromobutane (487 mg, 3.56 mmol) for 20 min gave 1 6 4 as a colorless oil

(105 mg, 48%):1H NMR (200 MHz. CDCfc) S -0.01 (s, 9H, SiMe 3 , E). 0.42 (s, 9H, SiMe 3 , Z), 0.75-

0.97 (m, 5H, CH 3 , CH2 ), 1.11-1.82 (m, 7H, CH 2 , CHSiM3 ), 7.49-7.63 (m, 3H, aromatic). 7.83-

7.88(m, 2 H, aromatic); 13C NMR (50 MHz, CDCfc) 8 -1.02 (CH3 , E), 1.51 (CH3 , Z). 11.11 (CH3 ,

Z), 12.72 (CH3 , E), 13.69 (CH 2 ), 14.31 (CH), 22.84 (CH 2 ), 29.68 (CH 2 ), 29.94 (CH 2 ). 30.13

(CH2 ), 41.50 (C, Z). 46.14 (C, E), 128.57 (CH, Z), 128.67 (CH, E), 131.90 (CH. Z). 133.15 (CH, E),

136.59 (CH). 139.31 (C); IR (neat) 2955, 2878. 1615, 1585, 1445, 1305, 1250, 1140, 1085,

910, 840, 760, 730, 690, 645 cm*1; exact mass calcd for C 1 (jH2 5 0 2 SSi: m/e 310.1423, found

m/e 310.1403. Anal. Calcd for C ieH 2 5 0 2 SSi: C, 61.89; H, 8.44. Found: C, 61.83; H, 8.38.

1-(Benzenesulfonyl)-1-(1-hexyl)-2-(trlmethylsilyl)cyclopropane(165).

SQ>Ph

Use of general procedure A with 8 (340 mg, 1.34 mmol), n -butyllithium (1.63 mL, 1.47 mmol,

0.90 M in hexanes), and 1-iodohexane (850 mg, 4.0 mmol) for 15 min yielded 1 6 5 as a yellow oil

(235 mg, 52%): 1 H NMR (200 MHz, CDCI3 ) 8 -0.01 (S. 9H. SiMe 3 , E), 0.42 (s, 9H, SIM 0 3 , Z),

0.79-0.97 (m, 6 H, CH3 .CH 2 ), 1.10-1.82 (m, 1 0 H,CH2 's), 7.49-7.63 (m, 3H, aromatic), 7.82-7.88

(m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 6 -1.02 (CH3 , E), 1.51 (CH3 , Z), 11.61 (CH3 , Z).

12.65(CH3, E), 13.69 (CH 2 , Z), 13.95 (CH 2 , E). 14.31 (CH, Z). 14.36 (CH, E), 22.44 (CH2 , E),

22.90 (CH 2 .Z), 26.10 (CH2 .Z), 27.50 (CH2 , E). 29.46 (CH 2 , Z), 29.68 (CH 2 , Z), 30.25 (CH2 , E), 65

31.36 (CH2 , E). 41.50 (C. 2), 46.19 (C, E). 120.56 (CH, E), 128.69 (CH, Z), 128.88 (CH, 2),

133.14 (CH. E). 136.59 (CH 2 , Z), 139.34 (C, E), 144.80 (C, Z); IR (neat) 2930, 2860,1615, 1585,

1445, 1305, 1250, 1140, 1085, 915, 840, 730, 690, 645 cm*1; exact mass calcd for

C i 8 H3 o0 2 SSi:m/e 338.1736, found m/e 338.1727. Anal. Calcd for Ci 8 H3 ()0 2 SSi: C, 63.85;

H. 8.93. Found: C, 63.69; H, 8.95.

(E)-1-(Benzenesulfonyl)-l-(benzyl)-2-(trimethylsilyl)cyclopropane(166).

Cl-fePh

Upon following general procedure A with 8 (147 mg, 0.578 mmol), n -butyllithium (0.71 mL, 0.636 mmol, 0.90 M in hexanes), and benzyl bromide (148 mg, 0.867 mmol) for 1.5 h afforded 1 6 6 (120 mg, 60%) as a colorless oil:1H NMR (200 MHz. CDCfe) 5 0.07 (s, 9H, SiMe 3 ), 1.07-1.30 (m, 2H,

CH2 ). 1.94-2.05 (m, 2H, CHSiMe 3 ), 2.71 (5, J - 6.4 Hz, 1 H, CHHPh), 3.46 (5, J - 6.4 Hz, 1 H,

CHHPh), 7.04-7.91 (m, 10H, aromatic); 13C NMR (50 MHz, CDC^) 8 -0 93 (CH 3 ), 12.54 (Cl-fe),

15.71 (CH), 35.57 (C), 46.09 (CH 2 ), 126.47 (CH), 128.03 (CH), 128.55 (CH), 128.58 (CH),

128.91 (CH), 132.79 (CH). 137.24 (C). 139.69 (C); IR (neat) 2955, 1595, 1495, 1445, 1305,

1250, 1145, 1090, 910, 840, 730 cm*1; exact mass calcd for C i 9 H2 4 0 2 SSi: m/e 344.1266, found m/e 344.1295. Anal. Calcd for C igH 2 4 0 2 SSi: C, 66.23; H, 7.02; found: C, 64.69; H,

7.13. 86 (E)>1-(Allyl)>1>(benzenesulfonyl)'2-(trimethylsilyl)cyclopropane (167).

Following general procedure A with 8 (123 mg, 0.483 mmol), n-butyllithium (0.41 mL, 0.532 mmol, 1.30 M in hexanes), and allyl bromide (292 mg, 2.42 mmol) for 30 min provided 1 6 7 (112 mg, 78%) as a colorless oil: 1H NMR (200 MHz. CDCI 3 ) 6 0.00 (s, 9H, SiMe 3 ), 0.76 (dd, J - 4.6 Hz,

8 .8 H, 1 H, cyclopropyl H), 0.98 (dd, J - 9.0,11.5 Hz, 1H, cyclopropyl H), 1.81 (dd, J - 3.0, 7.1 Hz,

1H, cyclopropyl H), 2.14 (dd, J - 4.6,9.5 Hz, 1H, allyl H), 2.50 (dd, J - 4.6, 9.5 Hz Hz, 1H, allyl H),

4.82-4.94 (m, 2H, vinyl H), 5.70-5.85 (m, 1H, vinyl H), 7.48-7.62 (m, 3H, aromatic), 7.82-7.87 (m,

2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 5 -1.20 (CH3 ), 12.60 (CH2 ), 14.45 (CH), 34.20 (CH2 ),

45.60 (C), 116.66 (CH2 ), 128.77 (CH). 128.84 (CH), 133.26 (CH), 134.73 (CH), 138.99 (C); IR

(neat) 3070, 2955, 1640, 1585, 1445, 1305, 1250, 1145, 1090, 1000, 920, 840, 790, 760cm-1; exact mass calcd for C i 5 H 2 2 0 2 SSi; m/e 294.1110, found m/e 294.1105. Anal. Calcd for

C 1 5 H 2 2 O 2 SS: C, 61.18; H, 7.53. Found: C, 61.10; H, 7.58.

General Procedure B for Fluoride Ion Reaction with 1-(Benzenesulfonyl)-2-

(trlmethylsllyl)-l-(substltuted)cyclopropanes:1-(Benzenesulfonyl)-1-

(methyl)cyclopropane(l 71).

Me 87

A mixture ot 1 6 3 (84 mg, 0.313 mmol) and TBAF (0.63 mL, 0.630 mmol, 1.0 M in THF) in dry THF

(2.0 mL) was refluxed under argon lor 30 min, diluted with diethyl ether (20 mL), washed with water (20 mL) and brine (20 mL), dried (MgSCX*), filtered, and concentrated in vacuo to a brown oil which was chromatographed (silica gel; ethyl acetate petroleum ether,1:5) to afford 1 71 (28 mg,

45%) as a colorless ol: 1H NMR (200 MHz, CDCfc) 6 0.78-0.83 (m, 2 H, CH2 ), 1.32 (s, 3H, CH3 ),

1.59-1.61 (m, 2H, CH 2 ), 7.50-7.63 (m, 3H, aromatic), 7.83-7.88 (m, 2 H, aromatic); 13C NMR (50

MHz, CDCfc) 5 12.95 (CH 3 ). 18.07 (CH 2 ), 37.32 (C). 128.70 (CH), 129.01 (CH), 132.72 (CH),

138.39 (C); IR (neat) 3065, 2970, 1585, 1445, 1305, 1145, 1085, 810, 760, 725, 690 cm*1; exact mass calcd for C 1 0 H 1 2 O 2 S: m/e 196.0558, found m/e 196.0550.

1>(Benzenesulfonyl)-i-(cyclopropyl)pentana (172).

SOfePh

Useof general procedure B with 1 6 4 (105 mg, 0.338 mmol) and TBAF (0.68 mL, 0.680 mmol,

1.0 M in THF) in dry THF (2.0 mL) for 0.5 h gave 1 7 2 (47 mg, 58%) as a colorless oil: 1H NMR

(200 MHz, CDCI3 ) 8 0.81-1.03 (m, 5H, CH 3 , CH2 ), 1.21-1.40 (m, 4H, CH2 ), 1.50-1.70 (m, 4H, cyclopropyl H), 7.52-7.65 (m, 3H, aromatic), 7.85-7.90 (m, 2H, aromatic); 13CNMR (50 MHz,

CDCfc) 811.21 (CH 3 ), 13.76(CH2 ). 22.63 (CH2 ). 28.09 (CFfc), 30.38 (CH 2 ), 41.37 (C). 128.65

(CH), 129.00 (CH), 133.28 (CH), 138.96 (C); IR (neat) 2960, 1585, 1445, 1300, 1140, 1085,840,

760, 725, 690, 650 cm*1; exact mass calc'd for C 1 3 H 1 8 O 2 S: m/e 238.1028, found m/e

238.1014. 88 l-(Benzeneaulfonyl)-i-(cyciopropyl)heptane (173).

A ; nC®H1 3 SOfePh

Following general procedure B with 1 6 5 (75 mg, 0.295 mmol) and TBAF (1.5 mL, 1.50 mmol,

1 .0 M in THF) for 30 min gave 1 7 3 (59 mg, 75%) as a colorless oil:1H NMR (200 MHz, CDCI 3 ) 5

0.78-0.90 (m, 5H, CH 3 CH2 ), 1.05-1.32 (m, 8 H, Chfe'S), 1.48-1.67 (m, 4H, Ofe'S), 7.51-7.64 (m,

3H, aromatic), 7.84-7.84 (m, 2 H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 11.22 (CH2 ). 13.96

(CH2 ). 22.44 (CH2 ), 25.91 (CH 2 ). 29.17 (CH 2 ), 30.68 (CH 2 ), 31.43 (CH2 ), 41.38 (C), 128.63

(CH), 128.99 (CH), 133.25 (CH), 139.00 (C); IR (neat) 2950, 2860, 1445, 1300, 1140, 1085,

1040, 915, 760,720, 690, 650 cm*1; exacl mass calcd for C 1 5 H2 2 O 2 S: m/e 266.1341, found m/e 266.1360.

1-(Benz0nesul1onyl)*l-(benzyl)cyclopropane(174).

Use of general procedure B with 1 6 6 (63 mg, 0.183 mmol) and TBAF (0.37 mL, 0.370 mmol, 1.0

M in THF) for 30 min gave 1 7 4 (35 mg, 70%) as a colorless oil:1H NMR (200 MHz, CDCI3 ) 5 0.60- B9

0.69 (m, 2 H, CH2 ). 1.48-1.60

7.07-7.22 (m, 3H, aromatic). 7.48-7.68

(50 MHz. CDCb) 8 9 3 4 (0 (2 ), 34.52 (CH2 ), 41.36 (C). 127.02 (CH), 128.31 (CH), 128.77 (CH),

129.05 (CH), 130.09 (CH). 133.35 (CH). 138.68 (C); IR (neat) 3030, 2925, 1585, 1495, 1445,

1305, 1140, 1080, 1040, 915, 845, 785, 725, 690cm*1; exact mass calcd for C 1 6 H 1 6 O 2 S: m/e

272.0871, found ffVe272.0867.

1-(Allyl)-l-(benzenesulfonyl)cyclopropane (175).

Reaction of 1 6 7 (102 mg, 0.346 mmol) and TBAF (0.69 mL, 0.690 mmol) for 30 min according to general procedure B afforded 1 7 5 (40 mg, 52%) as a colorless oil: 1H NMR (200 MHz, CDCIa) 6

0.88-1.0 (m, 2H, cyclopropyl H), 1.50-1.78 (m,2H, cyclopropyl H), 2.43-2.51 (m, 2H, CH 2 ), 4.90-

5.10(m , 2H, vinyl H), 5.40-5.62 (m, 1H, vinyl H), 7.55-7.67 (m, 3H, aromatic), 7.85-8.00 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 6 10.14 (CH2 ). 34.01 (CH2 ), 40.72 (C), 119.05 (CH 2 ),

128.79 (CH). 129.05 (CH), 132.08 (CH), 133.41 (CH), 138.62 (C); IR (neat) 3070, 3015, 1640,

1585, 1445, 1305, 1140, 1085, 915, 800, 730, 690 cm*1; exact mass calcd for C 1 2 H 1 4 O2 S: m/e

222.0715, found m/e222.0713. 90 (E)-1-(Benz0n»sulfonyl)-2-(trimethyl8llyl)*1-[2*(1-ph«nylethanol)]cyclopropan«

(1 8 0 ).

SQjPh

ChfeCH(OH)Ph

Following general procedure A, reactions of 8 (206 mg, 0.810 mmol), n-butyllithium (0.64 mL,

0.891 mmol, 1.4 M in hexanes), and styrene oxide (146 mg, 1.22 mmol) for 1.5 h yielded 1 8 0

(120 mg, 40%) as a white solid: nr*> 133-136°C; 1H NMR (200 MHz, CDCfc) 6 -0.11 (s, 9H,

SiMe3 ), 0.61 (dd, J - 4.7, 9.0 Hz. 1 H, CH), 0.80 (dd, J - 4.7, 9.0 Hz, 1 H, CH), 1.55 (dd, J - 5.3,

10.7 Hz, 1 H,CHSiMe3 ), 1 . 8 6 (dd, J - 3.6, 10.6 Hz, 1 H.CH), 2.31 (dd, J - 6 .8 , 15.0 Hz, 1 H, CH),

3.78 (s, 1 H, OH), 5.10 (m, 1 H, CH(OH)), 7.28-7.35 (m, 5H, aromatic), 7.54-7.71 (m, 3H, aromatic).

7.89-7(94, m, 2H, aromatic);13C NMR (50 MHz, CDCI 3 ) 6 -1 . 2 1 (CH3 ), 13.53 (CH2 ), 14.65 (CH),

39.75 (C), 44.55 (CH2 ), 72.33 (CH), 125.83 (CH), 127.56 (CH), 128.51 (CH), 128.70 (CH),

129.12 (CH), 133.62 (CH), 138.12 (C). 144.13 (C); IR (KBr) 3485, 3065, 2955, 1585, 1490,

1450, 1400, 1370, 1280, 1250, 1140, 1040, 985, 840,760, 730, 700 cm’ 1; exact mass cakf for

C 2 0 H 2 6 O3 SSi: m/e 374.1372, found m/e 374.1354. Anal. Calcd forC 2 0 H 2 6 C>3 SSi: C, 64.13;

H, 7.00. Found: C, 63.24; H, 6.90.

(E)- and (Z)- 1-(Benzenesulfonyl)-2-(trlmethylsllyl)-1-[1-(2- propanol)]cyclopropane (181).

SCfePh 91

Upon following general procedure A with8 (111 mg, 0.436 mmol), n-butyllithium <0.37 mL, 0.480

mmol, 1.30 M in hexanes), and propylene oxide (127 mg, 2.18 mmol) for 8 h gave 181 (60 mg,

44%) as a colorless oil:1H NMR (200 MHz, CDCI3 ) 6 -0.08 (s, 9H, SiMe 3 , E), -0.01 (s, 9H, SiMe 3 ,

2), 0.73-0.86 (m, 2H, 2 cyclopropyl H's), 1.04-1.34 (m, 4H, CH 3 , CHSiMe3 ), 1.80-2.00 (m, 2H,

CH2 ). 3.87 (bs, 1 H, OH), 3.97-4.05 (m, 1 H, CHOH), 7.47-7.66 (m, 3 H, aromatic), 7.78-7.85 (m,

2 H, aromatic); 13C NMR (CDCI 3 ) 6-1.30 (CH3 , E), -0.97 (CH 3 , 2). 11.34 (CH2 . 2 ), 13.43 (CH2 , E),

14.46 (CH, E), 14.87 (CH, 2 ), 23.55 (CH3 ), 39.14 (CH 2 , E), 39.63 (CH 2 . 2). 43.85 (C, 2), 45.05

(C, E), 63.74 (C, 2), 66.21 (C, E), 128.34 (CH, 2), 128.53 (CH, E), 128.97 (CH, 2), 133.42 (CH, 2),

133.50 (CH. E). 137.85 (C. 2), 138.07 (C, E): IR (neat) 3500, 3065, 2960, 1585, 1445, 1440,

1375, 1300, 1250, 1140, 1080, 980, 915, 840, 730, 690, 650 cm'1; exact mass calcd for

C is H 2 3 0 2 SSi (M+ - OH): m/e 295.1189, found m/e 295.1197; Anal. Calcd for C tsH 2 4 0 3 SSi:

C, 57.65; H, 7.74. Found: C, 57.59; H. 7.69.

(E)-1-(Benzenesulfonyl)-2-(trimethylsllyl)-1-(phenylmethanol)cyclopropana

(1 8 7 ).

SOfePh

CH(OH)Ph

Use of general procedure A withS (162 mg. 0.637 mmol), n -butyllithium (0.78 mL, 0.700 mmol,

0.90 M in hexanes), boron trifluoride etherate (108 mg, 0.764 mmol), and benzaktehyde (101 mg,

0.955 mmol) for 1 5 h afforded 1 8 7 (126 mg, 55%) as a colorless oil:1H NMR (200 MHz, CDCI3 )

6 0.10 (s, 9H, SiMe 3 ), 1.09-1.28 (m, 2H, cyclopropyl H), 1.97-2.03 (m, 1 H, CHSiMea), 3.35 (5, 92

J-7.5 Hz, 1 H, CHOH), 4.94 {5, J-7.5 Hz, 1 H, OH), 7.03-7.44 (m, 10H, aromatic); 13C NMR (50

MHz,CDC(3)8-0.46(CH3), 13.25 (CH), 14.21 (CH 2 ), 52.30 (C), 71.86 (CH), 126.55 (CH), 127.49

(CH), 127.87 (CH), 128.19 (CH), 128.56 (CH), 132.67 (CH), 139.63 (C), 139.88 (C); IR (neat)

3500, 3070, 3035, 2950, 1615, 1585,1445, 1300, 1250, 1140, 1050, 910, 840, 730 cm-1; exact mass calcd for C i^ H z i 0 3 SSi (M+ - CH3 ): m/e 345.0981, found m/e 345.0974. Anal.

Calcd for C i 9 H 2 4 0 3 SSi: C, 63.29; H, 6.71. Found: C, 62.44; H, 6.81.

(E)- and (Z)> 1-(Benzenesulfonyl)-1-[1-(2-methylpropanol)]-2-

(trlmethylsllyl)cyclopropane (188).

SOfePh

Upon following general procedure A with 8 (103 mg, 0.405 mmol), n-butyllithium (0.40 mL, 0.486 mmol. 1.2 M in hexanes), isobutyraldehyde (146 mg, 2.02 mmol), and boron trifluoride etherate

(287 mg. 2.02 mmol) for 3h gave 1 8 8 (64 mg, 49%) as a colorless oil: 1H NMR (200 MHz, CDCI 3 ) d 0.10 (S, 9H, SiM 6 3 ), 0.56 (d, J - 6.5 Hz, 3H, CH3 ), 0.94 (d. J - 6.5 Hz. 3H, CH 3 ), 0.87-1.05

2H, cycloproyl H), 1.78(dd, J-3.9, 6 . 8 Hz Hz, 1H, CHSiMe3 ), 2.10-2.19 (m, 1H, OH), 2.62-2.75

(m, 1 H, CH), 7.49-7.63 (m, 3H, aromatic), 7.87-7.92 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) d (CH3 ), 11.95 (CH3 ), 16.48 (CH3 ), 19.43 (CH), 20.98 (CH2 ), 33.82 (CH), 49.18 (C), 81.16 (CH),

128.77 (CH), 128.89 (CH), 133.44 (CH), 141.21 (C); IR (neat) 3530, 3060, 2960, 1585, 1470,

1445, 1290, 1250, 1140, 1090, 1040, 975, 840, 730, 690 cm'1; exact mass calcd for

C i 6 H 2 6 0 3 SSi: m/e 326.1372, found m'e326.1376. Anal. Calcd for C 1 6H2 6 0 3 SSi: C, 58.85;

H, 8.03. Found: C, 58.57; H. 7.85. 93

l-(Benzenesulfonyl)-1-(cyclopropyl)-3'(hydroxyl)*3’(ph«nyl)propan« (192).

SOfePh

Use of general procedure B with 1 8 0 (120 mg, 0.320 mmol) and TBAF (0.64 mL, 0.640 mmol,

1 .0 M in THF) for 30 min yielded 1 9 2 (53 mg, 55%) as a colorless oil: 1H NMR (200 MHz, CDCfe) 8

0.79-0.91 (m. 2H. cyclopropyl H), 1.09-1.15 (m, 2H, cyclopropyl H), 1.86 (dd, J - 4.0, 5.7 Hz Hz,

2H, CH 2 CH(OH)), 2.46 (bs, 1 H, OH), 5.04-5.10 (m, 1H.CH(OH)), 7.23-7.32 (m, 5H, aromatic),

7.54-7.68 (m. 3H, aromatic), 7.90-7.95 (m, 2 H, aromatic); 13C NMR (50 MHz, CDCfc) 8 11.80

(CH2 ), 13.21 (CH2 ), 40.01 (C), 41.88 (CH 2 ), 72.01 (CH), 125.55 (CH), 127.59 (CH), 128.46 (CH),

128.69 (CH), 129.24 (CH), 133.64 (CH), 138.20 (C), 141.06 (C); IR (neat) 3500, 3060, 2930,

1585, 1495, 1300, 1140, 1080, 910, 805, 755, 730, 690, 660 cm'1; exact mass calcd for

C 1 7 H 1 8 O 3 S: m/e 302.0977, found m/e302.0981.

i>(Benzenesulfonyl)-1-(cyclopropyl)-3'(hydroxyl)butane (181).

,CI-feCH{OH)CI-b

SCfePh

Reaction of 1 81 (123 mg, 0.394 mmol) and TBAF (0.79 mL, 0.790 mmol, 1.0 M in THF) for30 min 94

according to general procedure B provided 1 9 3 (74 mg, 78%) as a colorless oil: 1H NMR (200

MHz, COCI3 ) 5 0.90-1.08 (m, 2 H, cyclopropyl H), 1 . 1 1 (8 , J - 6.3 Hz Hz, 3H, CH3 ). 1.50-1.71 (m,

4H, cyclopropyl H, CH 2 ), 3.1 (bs, 1H. Oh), 4.07-4.13 (m, 1H, CH(OH)), 7.52-7.66 (m, 3H,

aromatic), 7.85-7.90 (m, 2 H, aromatic);13C NMR (50 MHz, CDCfc) 8 11.52 (CH2 ). 13.60 (CH2 ),

23.72 (CH3 ), 40.18 (C). 41.52 (CH 2 ), 65.82 (CH), 128.64 (CH), 129.20 (CH), 133.62 (CH),

138.02 (C); IR (neat) 3500, 2965, 1585, 1445. 1300, 1140, 1085, 915,850, 805, 760, 730, 690

cm'1; exact mass calod for C 1 2 H 1 6 ^ 3 S: m/e 240.0820, found m/e240.0812.

1-(Benzenesulfonyl)-i-(cyclopropyl)>2-(hydroxyl)-2-(phenyl)ethane(i95).

,CH(OH)Ph

SCfcPh

Reaction of 1 8 7 (63 mg, 0.168 mmol) and TBAF (0.34 mL, 0.340mmol, 1.0 M in THF) for 30 min

using general procedure B provided 1 9 5 (25 mg, 52%) as a colorless oil: 1H NMR (200 MHz,

CDCI3 ) 6 0.34-0.45 (m, 1H, cyclopropyl H), 1.03-1.15 (m, 1 H, cyclopropyl H), 1.34-1.44 (m, 1H, cyclopropyl H), 1.66-1.75 (m, 1H, cyclopropyl H), 3.67 (s, 1H, CH), 5.29 (s, 1H. OH), 7.00-7.04 (m.

2H, aromatic), 7.17-7.25 (m, 3H, aromatic), 7.54-7.74 (m, 3H, aromatic), 7.87-7.95 (m, 2H,

aromatic); 13C NMR (50 MHz, CDCI 3 ) 6 6 . 6 6 (CH3 ). 13.12 (CH3 ), 47.11 (C). 71.00 (CH), 126.50

(CH). 128.15 (CH), 128.68 (CH), 129.21 (CH), 129.28 (CH), 133.80 (CH), 137.47 (C), 138.39 (C);

IR (neat) 3500, 2955, 1585,1495, 1450, 1415. 1300, 1185, 1140, 1080, 1045, 755, 725, 690 cm'1. 95 1-(Benzenesulfonyl)>1-(cyclopropyl)-2>(hydroxy)-3-(methyl)bulane (196).

SOfePh

Use of general procedure B with 1 8 8 (55 mg, 0.168 mmol) and TBAF (0.34 mL, 0.340 mmol, 1.0

M in THF) yielded 1 9 6 (26 mg. 60%) as a colorless oil: 1H NMR (200 MHz, CDCI 3 ) d 0.54 (d, J -

6 . 6 Hz, 3 H.CH 3 ), 0.90 (d, J -6 .5 Hz, 3H, CH 3 ), 1.11-1.16 (m, 2H, cyclopropyl H), 1.25-1.30 (m,

1H, CH), 1.62-1.70 (m. 2H, cyclopropyl H), 2.51 (d, J - 5.6 Hz, 1H, CH), 3.24-3.31 (m, 1H, OH),

7.53-7.67 (m, 3H, aromatic), 7.88-7.93 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) d 10.45

(CH2 ), 18.92 (CH 3 ), 19.51 (CH 3 ), 31.36 (CH), 45.50 (C), 128.72 (CH), 129.08 (CH), 133.61 (CH),

139.37 (C); IR (neat) 3520, 2960, 1585, 1445, 1300, 1140, 1080, 1050, 785, 730, 695 cm'1; exact mass calcd lor C i 3 H i 8 0 3 S:nVe 254.0977, found m./e254.0966.

l>(Benzenesulfonyl)-l-(cyclopropyl)-2-(hydroxyl)-2-(methyl)propane(197).

Following general procedure B with 1 8 9 (49 mg, mmol) and TBAF (0.32 mL, 0.320 mmol, 1 .0 M in

THF) for 30 min gave 1 9 7 (28 mg, 74%) as a colorless oil: 1H NMR (200 MHz, CDCfe) 6 1.23 (s, 96

6 H, CH3 ). 1.50-1.56 (m, 4H, cyclopropyl H), 2.73 (s. 1H. OH), 7.50-7.70 (m. 3H, aromatic), 7.90-

7.94 (m, 2H, aromatic);13C NMR (50 MHz, CDCfc) 5 10.80 (CH 2 ), 28.73 (CH 3 ), 49.60 (C), 70.78

(C), 128.65 (CH), 128.96 (CH), 133.31 (CH), 141.31 (C); IR (neat) 3520, 2955, 1585, 1445.

1300, 1130, 1080, 785, 760, 690 cm*1; exact mass calcd lor C 1 2 H 1 6 O 3 S: m/e 240.0820, found

m/e 240.0830.

(E)>1>(Benzeneaulfonyl)*l>(benzoyl)-2-(irlmethylsllyl)cyclopropane(202).

COPh

Use of general procedure A with8 (139 mg, 0.546 mol), n-buty (lithium (0.50 mL, 0.601 mmol, 1.2

M in hexanes), and benzoyl chloride (115 mg, 0.819 mmol) for 1h yielded 2 0 2 (134 mg, 81%) as

a yellow oil : 1 H NMR (200 MHz, CDCI3 ) 8-0.17 (s, 9H. SiMe 3 ), 0.95 (dd. J - 2.2. 10.7Hz, 1H, CH),

1.35 (dd, J - 4.8, 9.5 Hz, 1 H, CH), 2.31 (dd. J - 4.7, 11.5 Hz. 1H, CH), 7.37-7.74 (m, 8 H.

aromatic), 8.02-8.17 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 -2.11 (CH3 ), 14.54 {CH2 ),

16.15 (CH), 52.57 (C), 128.27 (CH). 128.73 (CH), 128.88 (CH), 130.51 (CH), 133.62 (CH).

133.80 (CH). 135.95 (C), 138.65 (C), 192.21 (C); IR (neat) 3060, 2950, 1725,1595, 1450, 1310,

1280, 1250, 1210, 1160, 1140, 1090, 980, 840, 760, 725 cm'1; exact mass calc'd for

C 1 8 H 2 2 O 3 SSI: m/e 346.1059, found m/e 346.1057. Anal. Calcd for C isH 2 2 0 3 SSi: C, 62.39;

H, 6.40. Found: C, 63.33; H, 6.21. 97 (E )- a n d (Z)-l-(Benzanasulfonyl)-l>(trimathylacatyl)<2-

(trlmethylsllyl)cycloopropane(203).

Following general procedure A withB (185 mg, 0.727 mmol), n-butyllithium (0.57 mL, 0.799 mol,

1.4 M in hexanes), and trimethylacetyl chloride (175 mg, 1.45 mmol) for15 min provided 2 0 3 (184 mg, 75%) as a white solid: mp 103-105°C°;1H NMR (200 MHz, CDCfc) 8 0.30 (s, 9H, SiMe 3 , E),

0.39 (S, 9H, SiMe 3 , Z), 1.18-1.62 (m, 12H, CMea, CHSiMe 3 , 2 cyclopropyl H's), 7.47-7.62 (m, 3H,

aromatic), 7.71-7.76 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 -0.03 (CH3 , E), 0.99 (CH 3 , Z),

13.86 (CH 2 . E), 16.70 (CH), 28.65 (Chfe. Z). 45.76 (C), 55.55 (C), 128.35 (CH). 128.80 (CH),

129.48 (CH.Z), 133.46 (CH. E), 136.36.CH (E), 139.79 (C, Z), 208.39 (C); IR (KBr) 2955, 1690,

1585, 1480, 1450, 1395, 1365, 1315, 1250, 1150, 1085, 1020, 845, 755, 725,690 cm*1; exact mass calcd for C i 6 H 2 3 0 3 SSi(M+-CH 3 ): m/e 323.1137, found m/e 323.1137. Anal. Calcd for

C i 7 H 2 6 0 3 SSi: C, 60.31; H, 7.74. Found: C. 60.15; H. 7.79.

Mathyl (E)- and (Z)- l-(benzenesulfonyl)-2-(trlmethylsilyl)-1- cyclopropanecarboxylate(204). 98

Following general procedure A, reactions of 8 (205 mg, 0.806 mmol), n-butyllithium (0.63 mL,

0.886 mmol, 1.4 M in hexanes), and methyl chloroformate (379 mg, 4.03 mmol) for 15 min afforded 2 0 4 (192 mg, 76%) as a colorless oil:1H NMR (200 MHz, CDCfe) 5 -0.01 (s, 9H, SiMe 3 ),

1.27 (dd. J -1.9, 10.1 Hz, 1 H, CHSiMeg), 1.65 (dd, J - 4.1, 6.0 Hz, 1 H, CHH), 2.12 (dd, J - 4.1,

7.9 Hz,CHH), 3.61 (s, 3H, OMe), 7.50-7.64 (m, 3H, aromatic), 7.90-7.95 (m, 2H, aromatic); 13C

NMR (50 MHz, CDCI3 ) 5 -1.66 (CH3 ), 17.24 (CH), 18.35 (CH 2 ), 49.09 (C), 52.41 (CH 3 ), 128.63

(CH), 128.95 (CH), 133.47 (CH). 139.88 (C), 167.15 (C); IR (neat) 2955, 1740, 1585, 1450,

1370, 1310, 1250, 1225, 1150, 1100, 1065, 1020 cm'1; exact mass calcd for C 1 3 H 1 7 0 4 SSi

(M +-CH 3 ): m/e 297.0615, found m/e 297.0624. Anal. Calcd for C i 4 H2 0 O4 SSi: C, 53.82; H,

6.45. Found: C, 53.67; H, 6.43.

Ethyl (E)- and (Z)- i-(benzenesulfonyl)-2-(trimethyl»llyl)-l- cyclopropanecarboxylate (205).

CCfeEt

SCfePh

Upon following general procedure A with8 (223 mg, 0.877 mmol), n-butyllithium (0.69 mL, 0.964 mmol, 1.4 M in hexanes), and ethyl chloroformate (476 mg, 4.39 mmol) for ihgave 2 0 5 (183 mg,

64%) as colorless oil:1H NMR (200 MHz, CDCI 3 ) 8 -0.05 ( s. 9H, SiMea), 1.07 (t, J - 7.0 Hz, 3H,

CH3 ), 1.25 (dd, J - 8.7, 14.5 Hz, 1 H, CHSiMe3 ), 1.54 (dd, J - 4.4, 8.1 Hz, 1 H, cyclopropyl H),

2.06 (dd, J - 4.0,11.8 Hz, 1 H, cyclopropyl H), 4.04 (q. J - 3.0 Hz, 2 H, OCH2 ). 7.40-7.62 (m, 3H, aromatic). 7.77-7.90 (m, 2 H, aromatic);13C NMR (50 MHz, CDCfe) 8 -1 . 6 8 (CH3 ). 13.57 (CH3 ). 99

17.02 (CH2 ), 17.97 (CH), 48.97 (C), 61.92 (CH 2 ), 128.75 (CH), 128.99 (CH), 133.27 (CH),

139.95 (C). 166.49 (C); IR (neat) 2955, 1740, 1450, 1370, 1310, 1250, 1150,1100, 1065, 1020 cm'1; exact mass cakxJ for C-i 4 H ig 0 4 SSi(M+-CH 3 ):nVe 311.0774, found m/e 311.077. Anal.

Calcd for C 1 5 H2 2 0 4 SSi: C. 55.18; H, 6.79. Found: C, 55.53; H, 7.03.

1-(Benzenesulfonyl)-1-(benzoyl)cyc1opropane(207).

,COPh

SCfePh

Following general procedure Bwith 2 0 2 (89mg, 0.248 mmol) and TBAF (0.50 mL, 0.500 mmol,

1 .0 M in THF) for 30 min provided 2 0 7 (30 mg, 44%) as a colorless oil: 1H NMR (200 MHz, CDCI3 )

8 1.60-2.05 (m, 2H, cyclopropyl H), 3.02-3.22 (m, 1H, cyclopropyl H), 3.47-3.56 (m, 1H, cyclopropyl H), 7.32-8.11 (m, 1 0 H. cyclopropyl H); 13C NMR (50 MHz, CDCI 3 ) 8 15.32 (CH2 ).

25.98 (CH 2 ), 42.14 (C), 127.65 (CH), 128.37 (CH), 128.79 (CH). 129.45 (CH). 130.07 (CH).

133.30 (CH), 133.89 (C), 136.34 (C); IR (neat) 2960, 1695, 1595, 1450, 1385, 1305, 1150,

1090, 985, 760, 690 cm'1; exact mass cakxt for C 1 6 H 1 4 O3 S: m/e 286.0664, found m/e

286.0669. 100 l-(Benzenesul1onyl)-l-(trimethylac0tyl)cyclopropane(2O8).

Use of general procedure B with 2 0 3 (mg, mmol) and TBAF (mL, mmol, 1.0 M in THF) for 30 min yielded 2 0 8 (mg. %) as a colorless oil :1 H NMR (200 MHz, CDCI3 ) 8 1.27 (s, 9H, CMe 3 ), 1.31-1.41

(m, 2 H.CH 2 ), 1.71-1.77 (m. 2H, CH2 ), 7.48-7.63 (m, 3H, aromatic), 7.73-7.78 (m, 2 H, aromatic);

1 NMR (50 MHz, CDCI3 ) 8 13.34 (CH3 ), 26.96 (CH 2 ), 27.80 (C), 49.28 (C). 128.63 (CH),

128.86 (CH), 133.62 (CH), 139.18 (C), 207.64 (C); IR (neat) 2960, 1740, 1585, 1480, 1445,

1370. 1290, 1150, 1090, 1045, 840, 790, 730, 690 cm'1; exact mass calcd for C 1 4 H 1 8 O3 S: m/e

266.0977, found m/e 266.0959.

Methyl l*(benzenesulfonyl)cyclopropane carboxylate (209).

SCfePh

Following general procedure B with 2 0 4 (mg, mmol) and TBAF (mL, mmol, 1.0 M in THF) for 30 min afforded 2 0 9 (mg, %) as a colorless oil: 1H NMR (200 MHz, CDCI 3 ) 8 1.67-1.73 (m, 2H, cyclopropyl H), 1.97-2.04 (m, 2H, cyclopropyl H), 3.63 (s, 3H, OCH 3 ), 7.51-7.65 (m, 3H, aromatic), 7.97-8.01 (m, 2H, aromatic); 13C NMR (50 Mhz, CDCI 3 ) 816.88 (CH 2 ), 44.27 (C), 52.71

(CH3 ), 128.72 (CH), 129.24 (CH). 133.62 (CH), 139.72 (CH), 167.25 (C); IR (neat) 3050, 2950, 101

1720, 1585, 1455, 1295, 1210, 1150, 990, 785, 750, 685 cm '1; exact mass calcd for

C 1 1 H 1 2 O 4 S: m/e 240.0456, found m/e 240.0467.

Ethyl-1-(benzenesulfonyl)cyclopropane carboxylate (210).

Use of general procedure B with 205 (75 mg, 0.230 mmol) and TBAF (0.46 mL, 0.460 mmol, 1.0

M in THF) for 30 min gave 210 (22 mg, 38%) as a colorless oil: 1H NMR (200 MHz, CDCI 3 ) d 1.13

(t, J = 7.1 Hz, 3H, CH3 ), 1.65-1.72 (m, 2H. CH2 ). 1.96-2.02 (m, 2 H, CH2 ), 4.06 (1, J = 7.1 Hz, 7.1

Hz, 2H, CH 2 ), 7.50-7.64 (m, 3H. aromatic), 7.96-8.00 (m. 2H, aromatic); 13C NMR (50 MHz,

CDCI3 ) d 13.74 (CH2), 16.80 (CH3), 44.15 (C), 62.12 (CH 2 ), 128.63 (CH), 129.15 (CH), 133.52

(CH), 166.74 (C); IR (neat) 3065, 2985, 1730, 1585, 1450, 1370, 1310, 1140, 1080, 1020, 960,

915, 850, 735, 690 cm'1; exact mass calcd for C 1 2 H 1 4 O 4 S: m/e 254.0613, found m/e

254.0617.

(E)-1,2-Bis(benzenesulfonyJ)cyclopropane (217).

Tetra-n -butylammonium fluoride (0.41 mL, 0.410 mmol, 1.0 M in THF) was syringed into a solution 102 of 1 5 2 (80 mg, 0.203 mmol) in dry THF (2.0 mL) at 0°C under argon. The brown mixture was stirred 5 h at room temperature, diluted with diethyl ether (20 mL), washed with water (20 mL) and brine (20 mL), dried (MgSQ4 ), filtered, and concentrated in vacuo to yield 21 7 (39 mg, 60%) as a white-brown solid: mp 175-177°C; 1H NMR (200 MHz, CDCfc) S 1.96 (t, J - 7.5 Hz, 2H, cyclopropyl H),3.19 (t, J - 7.6 Hz, 2 H, CHS 0 2 Ph), 7.42-7.76 (m, 10H. aromatic); 13C NMR (50

MHz. CDCb) 6 10.59 (CH 2 ), 38.82 (CH), 127.56 (CH). 129.48 (CH), 134.09 (CH), 138.84 (C); IR

(KBr) 3110, 3030, 1585, 1450, 1400, 1325, 1160, 1085, 900, 800, 730, 700, 590, 525 cm'1; exact mass calcd for C 1 5 H 1 4 O 4 S2 : m/e 322.0334, found m/e 322.0322.

(Z)-l-(Benzenesulfonyl)-1-bromo-2-(trlmethylsllyl)cyclopropane(222).

SCfePh

Following general procedure A, reactions of 8 (252 mg, 0.990 mmol), n-butyllithium (0.78 mL,

1.09 mmol, 1.4 M in hexanes), and bromine (316 mg, 1.98 mmol) for 15 min gave 2 2 2 as white solid (223 mg, 6 8 %): mp 73-75°C;1H NMR (200 MHz, CDCI3 ) 5 0.06 (s. 9H, SiMe 3 ), 1.16-1.34

(m, 2H, cyclopropyl H), 2.12 (dd, J - 3.5, 11.0 Hz, 1H, CHSiMeg), 7.52-7.67 (m, 3H, aromatic),

7.90-7.94 (m, 2H, aromatic);13C NMR (50 MHz, CDCI 3 ) 5 -1.65 (CH3 ). 14.31 (CH), 19.70 (CH 2 ),

49.70 (C), 128.79 (CH), 129.60 (CH), 133.92 (CH), 136.74 (C); IR (neat) 2955, 1615, 1585,

1450, 1325, 1250, 1150, 1090, 1040, 955, 910, 840, 740, 690 cm*1; exact mass calcd for

C i 2 H 1 7 Br0 2 SSi:m/e 331.9902, found m/e 331.9900. Anal. Calcd for C 1 2 H 1 7Br02SSi: C,

43.24; H. 5.14. Found: C, 43.28; H, 5.11. 103 1-(Benzenesulfonyl)-3,4-(dlmethyl)blcyclo[4.1.0.]hept>3-ene (223).

Reaction of 2 2 2 (281 mg. 0.843 mmol) and TBAF (1.70 mL, 1.70 mmol, 1.0 M in THF) in the presence of 2.3-dimethyl-1,3-butadiene (346 mg, 4.22 mmol) in dry THF (2.0 mL) at 25°C for 3 h using general procedure B gave 2 2 3 (150 mg, 6 8 %) as a colorless oil: 1H NMR (200 MHz,

CDCfc) d 0.82-0.90 (m, 1H, CH), 1.55 (S, 6 H, 2 CH3 ). 1 40-1.62 (m, 1H, CH), 2.0-2.70 (m, 5H,

CH2 , CH), 7.50-7.70 (m. 3 H, aromatic). 7.83-7.90 (m, 2 H, aromatic): 13C NMR (50 MHz. CDCfc) d

12.96 (CH 2 ), 17.76 (CH), 19.05 (CH 3 ), 19.13 (CH 3 ), 29.79 (CH 2 ), 30.01 (CH2 ), 40.91 (C),

120.44(C), 121.37 (C), 128.56 (CH), 129.05 (CH). 133.21 (CH), 138.68 (C); IR (neat) 3065,

3000, 2910, 2840, 1585, 1445, 1305, 1175, 1145, 1085, 915, 840, 790, 760, 730, 690,840 cm'1; exact mass calcd for C 1 5 H 1 8 O2 S: m/e 262.1028, found m/e262.1024.

(1a, 2 3 , 4 3 , 5a)-2-(Benzenesulfonyl)-8-oxatrlcyclo(3.2.1.0 2 * 4 ]oct- 6 -ene (224).

SCfePh

Following general procedure B with 2 2 2 (138 mg, 0.414 mmol) and TBAF (0.83 mL, 0.830 mmol,

1.0 M in THF) in the presence of furan (170 mg, 2.07 mmol) in dry THF (2.0 mL) at 25^C for 30 min 104 gave 2 2 4 (56 mg, 55%) as a colorless oil: 1H NMR (200 MHz, CDCfc) 8 1.83 (dd, J-2.1, 5.2 Hz.

1H, cyclopropyl H), 2.12 (dd, J-1.0, 4.3 Hz, 1H, cyclopropyl H), 2.43 (dd, J-3.0, 4.4 Hz, 1H, cyclopropyl H), 4.74 (d, J-1.5 Hz, 1H, CHO), 4.77 (d, J-1.7 Hz, 1 H, CHO), 6.63 (dd, J-1.7. 4.0

Hz, 1 H, vinyl H). 6.71 (dd. J-1.5,4.0 Hz, 1H, vinyl H), 7.53-7.71 (m, 3H, aromatic), 7.85-7.94 (m.

2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 5 23.99 (CH 3 ), 33.91 (CH), 53.53 (C), 77.30 (CH),

78.87 (CH), 127.68 (CH), 129.29 (CH), 133.47 (CH), 137.85 (CH), 139.71 (CH), 140.57 (C); IR

(neat) 3055, 2995, 1640, 1580, 1445, 1310, 1150, 1085, 1060, 785, 765, 685 cm'1; exact mass calod 1o r C i 3 H i 2 O 3 S: m/e 248.0507, found m/e248.0505.

(E)-2-Methoxy-l-(benzenesulfonyl)cyclopropane (225).

MeO.

SOfePh

A solution of sodium methoxide prepared from sodium (42 mg, 1.82 mmol) in dry methanol (1.0 mL) was added dropwise to a mixture of 2 2 2 (173 mg, 0.519 mmol) and TBAF (1.04 mL. 1.04 mmol, 1 .0 M in THF) in dry THF (5.0 mL) at -78°C. After 4h at 25°C, 2 2 5 (43 mg, 39%) as brown oil was isolated: 1H NMR (200 MHz, COCI3 ) 5 1.39-1.49 (m, 1 H, cyclopropyl H), 1.57-1.67 (m, 1 H, cyclopropyl H), 2.47-2.56 (m, 1H. CHSO 2 PI1). 3.25 (S, 3H, OMe). 3.79-3.86 (m, 1H, CHOMe).

7.52-7.66 (m, 3H, aromatic). 7.88-7.94 (m. 2 H. aromatic); 13C NMR (50 MHz, CDCfe) 5 14.37

(CH2 ), 38.99 (CH), 58.74 (CH), 59.55 (CH 3 ), 127.44 (CH), 129.26 (CH), 133.50 (CH), 140.35 (C);

IR (neat) 3045, 2935, 1585, 1450, 1425, 1365, 1310, 1260, 1225, 1150, 1090, 1025,915, 865,

810, 735, 690 cm'1; exact mass calcd for C 1 0 H 1 2 O3 S: m/e 212.0507, found m/e 212.0502. 105 (E )- a n d (Z)-1 -(Benzenesulfonyl)-i-(trlfluoromethanesulfonyl)-2- (trlmethylsilyl)cyclopropanes (228).

SOfePh

To a solution of 8 (214 mg, 0.841 mmol) in dry THF (10 mL) at -78°C under argon was syringed in

n-butyllithium (0.50 mL, 1.0 mmol, 2.0 M in hexanes). After 20 min, trifluoromethanesulfonic

anhydride (332 mg, 1.18 mmol) was added dropwise to the dark orange solution. The mixture was

stirred 15 min, diluted with diethyl ether (20 mL), washed with water (10 mL) and brine (10 mL),

dried (MgS0 4 ), filtered, and concentrated in vacuo to a brown oil which was chromatographed

(silicagel; ethyl acetate; petroleum ether, 1;5) to afford 2 28 (155 mg, 50%) as a yellow viscous

Oil: 1 H NMR (200 MHz, CDCI3 ) 8-0.03 (s. 9H, SiMe 3 , E), 0.42 (s, 9H, SiMe 3 , Z), 1.23-1.27 (m,

2 H, CH2 ), 2.02-2.11 (m. 1 H. CH), 7.53-7.68 (m.3H, aromatic). 7.90-7.95 (m, 2H, aromatic) ; 1 3c

NMR (50 MHz, CDCI3 ) 5 • IR (neat) 3060, 2955, 1585, 1450, 1370, 1325, 1250, 1200, 1165,

1110, 1090, 845, 790, 755, 690 rm '1; exact mass calcd for C 1 3 H 1 6 F3 C>4 S2 Si (M+ - 1 ): m/e

385.0212, found m/e 385.0221.

(E)*1-(Bttnzenesulfonyl)-l*(styryl)*2*(lrlmathylsilyl)cyclopropane (235).

,SOfePh

Ph

A mixture of 1 80(151 mg, 0.403 mmol) and p-toluenesulfonic acid monohydrate (50 mg, 0.263 106 mmol) in dry benzene (5.0 mL) was refluxed 3h, cooled, washed with water (10 mL) and brine (10 mL), dried (MgSQ4 ), tittered, and concentrated in vacuo to a yellow oil which was chromatographed (silica gel; ethyl acetate; petroleum ether, 1:5) to afford 2 3 5 (110 mg, 77%) as a colorless oil: 1H NMR (200 MHz. CDCI 3 ) 5 0.01 (S, 9H, SiM 6 3 ), 1.16-1.38 (m, 2H, cyclopropyl

H), 1.76-1.87 (m,1H, CH), 6.30-6.35 (m, 2H. vinyl), 7.20-7.34 (m, 5H, aromatic), 7.45-7.61 (m, 3H, aromatic), 7.78-7.82 (m. 2 H. aromatic); 13C NMR (50 MHz, CDCfc) 8 -1.04 (CH3 ), 12.53 (CH).

14.73 (CH), 48.32 (C), 121.10 (CH). 126.45 (CH), 128.43 (CH), 128.58 (CH), 128.67 (CH),

128.70 (CH), 128.93 (CH), 133.19 (CH), 135.79 (C), 138.51 (C); IR (neat) 3060, 3020, 2995,

1600, 1585, 1445, 1305, 1250,1160, 1140, 1090, 915, 840, 730, 690 cm'1; exact mass calcd for C 2 0 H2 4 O 2 SSi: m/e 356.1267, found m/e 356.1265.

1 -(Benzenesulfonyl)-l-(styryl)cyclopropane (237).

Ph

A solution of 2 3 5 (55 mg, 0.154 mmol) and TBAF (0.31 mL, 0.310 mmol, 1.0 M in THF) indry THF

(2.0 mL) was refluxed 1 h according to general procedure to give 2 3 7 (22 mg, 52%) as a colorless oil: 1H NMR (200 MHz, CDCI3 ) 8 1.19-1.29 (m, 2 H, CH2 ), 1.78-1.84 (m, 2 H, CH2 ), 6.26 (d, J -

15.8 Hz. 1H, vinyl), 6.50 (d, J - 15.4 Hz, 1H, vinyl), 7.18-7.36 (m, 5H, aromatic), 7.45-7.65 (m, 3H, aromatic), 7.80-7.85 (m, 2H, aromatic); 13C NMR (50 MHz, CDCI 3 ) 8 13.21 (CH2 ). 44.30 (C),

122.00 (CH). 126.49 (CH), 128.39 (CH), 128.63 (CH), 128.75 (CH), 128.81 (CH), 133.33 (CH),

135.70 (CH), 136.45 (C), 138.5(C); IR (neat) 3055, 3025,2965, 1650, 1585, 1490, 1445, 1300,

1130, 1080, 965, 905, 735, 690 cm'1; exact mass calcd for C 1 7 H 1 6 O 2 S: m/e 284.0871, found m/e 284.0872. 107

Reaction of 165 with Potassium ferFButoxlde In tho Presence of 2,3-Dimethyl-

1 ,4-Butadiene to Give Cyclopropane 173.

Potassiumferf-butoxide (17 mg, 0.152 mmol) and 1 6 5 (43 mg, 0.127 mmol) in THF (5.0 mL) was heated at 500 C for 18 h in the presence of 2 ,3-dimethy 1-1,4-butadiene (104 mg, 1.27 mmol) under a blanket of argon. The white mixture was diluted with diethyl ether (20 mL), washed with water (20 mL) and brine (20 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to a

yellow oil which was chromatographed (silica gel, ethyl acetate petroleum ether, 1 :5) to yield 1 7 3

(25 mg, 75%) as a colorless oil.

Reaction of 165 and TBAF Treated with n-BuLI In the Presence of Furan to Give

Cyclopropanes 173.

To a solution of TBAF (0.27 mL, 0.270 mmol, 1.0 M in THF) and furan (185 mg, 2.72 mmol) in dry THF (5.0 mL) at 25°C was syringed in n-butyllithium (0.50 mL, 1.0 mmol, 2.0 M in hexanes) under argon. The mixture turned dark brown and vigorous bubbling occurred. After 10 min, when cessation of the bubbling was observed, a solution of 1 6 5 (46 mg, 0.136 mmol) in

THF (5.0 mL) was added to the mixture. After stirring for 1 h, the reaction was diluted with diethyl ether (20 mL), washed with water (20 mL), dried (MgSCX}), filtered, and concentratedin vacuo to a yellow oil which was chromatographed to give 1 7 3 (29 mg, 76%) as a colorless oil. CHAPTER II

1,1-(DIUTHIO)-1-(BENZENESULFONYL)-2-(TRIMETHYLSILYL)ETHANE AS

AN EFFECTIVE SYNTHETIC EQUIVALENT FOR SYMMETRICAL 1,1-

DISUBSTITUTED TERMINAL OLEFINS

I. Statement of Problem.

The present study involves generation and determination of the utility of 1,1-(dilithio)-1 -

(benzenesulfonyl)-2-(trimethylsilyl)ethane (243) as an effective intermediate for preparing 1 ,1 - disubstituted terminal olefins (245 , Scheme 56). The systems investigated involve reactions of 1-

(benzenesulfonyl)- 2 -(trimethylsilyl)ethane ( 1 ) with two equivalents of n-butyllithium and then two or more equivalents of varied alkyl halides to give disubstituted sulfones 244 which upon treatment with fluoride ion afford 245 advantageously. Previous studies of synthesis and mechanistic aspects of geminal dianions of sulfones will be summarized followed by presentation and discussion of the present research accomplishments.

Scheme 56. Synthetic Utility of 1,1-(dilithio)-1-(benzenesulfonyl)-2-(trimethylsilyl)ethane (243).

Li 2 eq. n-BuLi S 0 2Ph RX (excess) M e a S i^ ^ j^ 2BuH Li 243

S 0 2Ph = = 3 ^ + Me3SiF + S 02Ph R 109

II. Introduction.

Geminal dianions have become increasingly important for organic synthesis. Many of the recent advances in dianion chemistry have been reviewed by Thompson and Green .7 0 The use of geminal dianions as specifically applied to sulfones will now be summarized.

Synthesis and Chemistry of a, a- Dilithio Sulfones.

Hauser and coworkers were the first to study synthesis of gem-disubstituted sulfones from geminal dianion precursors. 7 1 Thus, treatment of N,N-dimethylbenzylsulfonylamide (246) with 2.2 equiv of n-butyllithium in THF was found to yield a,a-dilithio species 247 which reacts with two equivalents of deuterium oxide, methyl iodide, and 1,4-dibromobutane, respectively, to give geminal disubstituted products 248 efficiently (Equation 36).

Li R 2.2 eq n-BuLi | D2q 0r RX | PhCH2 SOzNMe2 THF 0°C-----** PhCS02 NMe2 ------► PhCS02 NMe2 (36) rue * * 2 4 6 Li R 247 248

R = D (81%)

R = Me (75%) R = -(C H Z)*- (90%)

Evans and Morr report preparation and dilithiation of tetrafluoroferrocenylmethyl phenyl sutfone (249) 7 2 Addition of two equivalents of n-butyllithium to 249 in THF at room temperature

results in dilithio derivative 250 which when quenched with two equivalents of deuterium oxide, methyl iodide, and 1 ,2 -dichloroethane, respectively, yields a-ferrocenyl disubstituted derivatives 110 251 {Equation 37). Addition of 1 -bromobutane or benzyl bromide to 250 however results only in monosubstitution of 250.

Li 2 n-BuLi 1 D20 or RX FcCH 2 S 02Ph FcCS02Ph ------Fc

R = D (95%)

R = Me (74%)

Fc = Fe, R = -(C H 2)2- (89%)

1,1-Dilithioallyl phenyl sulfone (255) and its isomer, 1-iithioallyl-o-lithiophenyl sulfone

(254), have been generated and used for geminal cycloalkylations (Equation 38).73 Reactions of allyl phenyl sulfone (252) and two equivalents of n-butyllithium give 254 and 255 which, upon addition of excess methyl iodide, yields 1,1-dimethylallyl phenyt sulfone (256, Scheme 57).

Similarly, reactions of 254/255 with 1,(o-dibromoalkanes provide carbocyclic compounds 257.

Ditosylates 258 and 259 and 254/255 result in bicyclic compounds 260 and 261 in high yields and diastereoselectivities (ds). 1H NMR spectroscopy reveals that the second lithiation of 1 -lithioallyl phenyl sulfone (253) proceeds remarkably. At -78°C in THF, the second equivalent of n- butyllithium metalates 253 in an ortho position of its phenyl group to give 254 kinetically controlled and in high selectivity as well in its 1-position to yield 255. Upon warming 254 to 50°C selectivity decreases and complete dimetallation to the thermodynamically more stable 1 ,1 -dilithio species 255 occurs. 111 1 eq n-BuLi ^jjjS^V^S°2Ph S 02Ph 1 eq n-BuLi H Li 252 253 (38) Li. *-0 H Li Li Li

254 255

Scheme 57. Reections of Allyl Dianion 254/255

S 02Ph S 02Ph (80%) Me Me " ' x

Mel n = 2 (44%) n = 3 (80%) n = 4 (89%)

254/255 OTs OC OTs c OTs 256 > c c OTs

S02Ph (77%, ds = 70%) oS02Ph

250

261 (82%. ds = 90%) 112

Gais et al have also examined synthesis, characterization, and uses of dilithio

(phenylsulfonyl)trimethylsilylmethane (264). 7 4 Lithiation of (phenylsulfonyl)trimethylsilylmethane

(262) with one equiv of rr-butyllithium in THF at -70°C leads quantitatively to the readily soluble monolithio sulfone 263 which upon further lithiation with one equiv of n-butyllithium in THF (-

70°C to 0°C ) gives 264 (Scheme 58) without prior orfho-metallation of the phenyl ring and subsequent transmetallation. 1H and 13C NMR spectroscopic evidence for 262 and lithio species 263 and 264 in THF-d 8 provided unequivocal evidence. Deuteration of 264 with deuterium oxide at -30°C affords dideutero sulfone 265, and reactions of 264 with methyl iodide at -78°C and 1,4-dibromobutane at 0°C result in 1,1-dimethyl sulfone 256 and cyclopentyl sulfone 267, respectively. Peterson olefination of 264 with benzaldehyde (-70°C to 0°C ) and then reaction with DCI/D 2 O/THF produce E- and Z- p-deuterostyryl phenyl sulfones 268.

Scheme 58. Generation and Reactions of Dilithio Anion 263

n-BuLi, THF V rvBuLi V' Me3 SiCH2 S 0 2Ph ------► Me3 Si-C-S02Ph ►Me3 S i- C - S 0 2Ph -70°C H -70°C-*- 0°C Li 262 253 264

? DzO or RX V PhCHO r , ,S° 2 Ph Me3 S i- C - S 0 2 P h ------Me3 Si-C-S02Ph ► C=C R U 02O h' NR

254 268 265 R = D (95%) R = D (55%)

266 R = Me (8 6 %) 267 R = - (CH2)4- (81%) 113 1H and 13C NMR spectroscopy prove the existence of a,o-dilithio sulfones of several alkyl phenyl sulfones . 7 5 Reactions of the lithium salts of 252, 269, and 270 give a,o-dilithio sulfones 253, 271, and 272, respectively (Equations 39-41). a,o-Dilithio cyclopentenyl phenyl sulfone (271) and a,o-dilithio bis(trimethylsilyl)methyl phenyl sulfone (272) cannot undergo geminal transmetallations. Unequivocal proofs for 253, 271, and 272, respectively, are obtained by the appearances of six new signals in the aromatic regions of their individual 13C NMR spectra.

(/ ^ n-BuLi, THF (39) * - o H Li 252

n-BuLi, THF (40)

259

n-BuLi, THF (41) Me3Siv - o

SiMe3 271

a,o-Dilithio ally I phenyl sulfone (253) has been used for synthesis of carbaprostacyclins

277 of value as endogenous inhibitors of blood platelet aggregation and as strong vasodilators.7 6

Treatment of a ,odilithio sulfone 252 with dimesylate 273 in THF at -30° C via alkyiation, transmetallation and geminal cycloalkylation leads smoothly to bicyclic sulfone 274 which 114 undergoes a S|sj2‘ reaction with cuprate 275 to give mixtures of exocyclic alkenes 276 which can

be converted to 277 (Scheme 59).

Scheme 59. Use of Allyl Dilithio Anion 253 in Synthesis of Carbaprostacyclins 277

OMs

0— OMs LiCu( 253 275

TBDMSO THF. -30°C TBDMSo' R = CH(Me)OEt OTBDMS OTBDMS 273 274

H 0 2 C(H2 C ) 3

TBDMSO h o ' OTBDMS OH 276 277

R' = /7-C5Hn R’ = CH(Me)CH2CCMe

Umani-Ronchi and coworkers have exploited sulfones 278 for syntheses of methyl jasmonate (282) and racemic methyl dihydrojasmonates (283), primary odorous principles of the

Jasminium flower oils, important raw materials in perfumes.7 6 Reactions of two equivalents of i>

butyllithium with sulfones 278 in THF/HMPA at -78°C give soluble dilithio derivatives 279 which when followed by additions of one equivalent of y-valerolactone afford (J-keto sulfones 280. Metal 115 reductions of 280, Jones oxidations, and cyclizations by bases yield cyclopentenones 281, which are precursors of methyl jasmonates 282 and 283 (Scheme 60).

Scheme 60. Syntheses of Methyl Jasmonates 282/2283 with Dilithio Sulfones 279

1, 0 - 0 2 eq n-BuLi O n u _ n w PhS0 2 CH2R PhS0 2 CRLi2 —— - r vn THF/HMPA « u <$> 278 m Ha° so2Ph

280

1. Al/Hg

2 . CrP 3 . pyridine

3. H cP C 0 2Me

292 R = n-CsHu

283 R - c /S - CH 3 CH 2 CHCHCH 3

Eisch and coworkers have utilized [(phenylsutfonyt)methylene]dilithium (89), as generated from methyl phenyl sulfone (284) and two equiv of n-butyllithium, as a novel cyclizing reagent for reaction with 1 ,2 -dichloroethane to prepare phenylsulfonylcyclopropane (88) in 60% yield

(Equation 42).22

Cl, 2 n - BuLi 'C l PhSC2Me ------► PhS0 2 CHLi2 ► — S 0 2Ph (42) THF, 0°C 284 88 116

III. Previous Background.

The synthetic utility of 1-(benzenesulfonyl)-2-(trimethysilyl)ethane (1) has been briefly examined by Kocienski 2 and Eisch e ta l 3 and exhaustively studied by Hsiao and Shechter . 1

Deprotonation of 1 by r>-butyllithium gives 1-(benzenesulfonyl)-1-(lithio)-2-(trimethylsilyl)ethane

(1 1 ), reactions of which with alkyl halides afford 2 -(benzenesulfonyl)- 1 -(trimethylsilyl)alkanes

(285) which can be converted to monolithio derivatives 286 by n-butyllithium. Subsequent

reactions of 286 with halides in HMPA yield geminal disubstituted sulfones 287 (Scheme 61).

Scheme 61. Synthetic Utility of 1>(Benzenesulfonyl)-2-(trimethylsilyl)ethane (1).

^ S 0 2Ph n-BuLi, THF .S 0 2Ph RX Me3s r Me3s r -78°C 1 1 Li 11

^ S 0 2Ph n-BuLi, THF S 0 2Ph R'X Me3S r y ' ► Me3 Si J & -78°C Lj 286 286 R . S0 2Ph Me3s r R' 287

Of present interest is that p -silyl sulfones 285 and 287 undergo efficient

debenzenesulfonyltrimethylsilylation by tetra-n-butylammonium fluoride in refluxing

tetrahydrofuran via 1 ,2 -elimination to afford monosubstituted terminal olefins 288 (Equation 43)

and 1,1-disubstituted terminal olefins 289 (Equation 44), respectively. Thus 1 can be considered

to be an efficient synthon for vinyl anion 12 and vinyl 1 ,1 -dianion 13. 117

S02Ph TBAF, THF, 65°C Me3 St (43) R 285

S 02Ph TBAF, THF. 65°C R Me3 Six 's|^' (44) R' , 2B7 245

0 0 "© H 12 13

The present study involves a simplified route of 1 to 244 via dianion chemistry without proceeding through intermediates 11, and 285-286 and subsequent 1,2-elimination of 287 to symmetrical 1,1-disubstituted terminal olefins 245.

IV. Results and Discussion.

Preparation of 1-(Benzenesulfonyl)-2-(trimethylsilyl)ethane (1).

1-(Benzenesulfonyl)-2-(trimethylsilyl)ethane (1) is obtained conveniently in quantity by (1) homo lytic addition of thiophenol to trimethyl(vinyl)silane (133) at 110°C in the presence of catalytic quantitites of azoisobutyronitrile (AIBN) and (2) oxidation of the resulting 1-

(thiophenoxy)-2-(trimethylsilyl)ethane (289) with excess hydrogen peroxide (30%) in warm acetic acid (Scheme 62). 118 Scheme 62. Preparation of 1-{Benzenesulfonyl)-2-{trimethylsilyl)ethane (1)

PhSH, AIBN SPh H 2 0 2. HOAc SiMe3 Me3S i'^ -'S°2Ph

133 209 1

Studies of Dialkylation of 1-

Generation and diaikylations of 243 with varied halides have been studied. The general procedure developed involves rapid addition of 2.5 equivalents of n-butyllithium to 1 in tetrahydrofuran at -78°C, storage of the mixture at -78°C for 20 min and at room temperature for

1.5 h to give 243 followed by displacement of a halide (4-10 equiv) to yield 2,2-(dialkyl)-2-

(benzenesulfonyl)- 1 -(trimethylsilyl)alkanes (244, Scheme 63).

Schama 63. Dialkylation of 1-(Benzenesulfonyl)*2-(trimethyl8iiyl)ethane (1) with Alkyl Halidas

Li 2.5 eq n-BuLi, THF S 0 2Ph Me3 Si'''^ -78°C — 25°C Li

243

R RX (4-10 eq) l\,S 0 2Ph Me3Si R 244

To determine whether dilithio intermediate 243 is generated the following deuterium labelling experiment was completed. Reaction of 243 with 2.5 equivalents of n-butyllithi jm in tetrahydrofuran for 20 min at -78°C followed by stirring the resulting mixture at 25°C for 1.5 h 119 and then addition of deuterium oxide affords 1 -(benzenesulfonyi)- 1 , 1 -(dideutero)-2 -

(trimethylsilyl)ethane (290, Equation 45). The 200 MHz 1 H NMR spectrum of 290 reveals 85% incorporation of two deuterium atoms onto the a-sutfonyl carbon. Furthermore, reaction of 1 with

2.5 equivalents of n-butyllithium in tetrahydrofuran for 20 min at -78°C followed by stirrring at

25°C for 1 .5 h and then removal of the solvent under high vacuum gave a brown crystalline solid

^SO?Ph 1. 2.5 eq n-BuLi, THF — . | ^SOpPh Me3Sr Me3Sr (4s) -78°C-7R°P. —— 25 25°C C I D

2 D2 ° 290

whose 1H NMR (200 MHz) in THF-d8 reveals five protons for the aromatic hydrogens and whose

13C NMR (63 MHz) in THF-d8 shows four aromatic carbons. These data suggest that a,a-

(dilithio)-1-(benzenesutfonyl)-2-(trimethylsilyl)ethane (243) is formed in reactions of two equivalents of n-butyllithium with 1 .

Primary bromides and iodides such as methyl iodide, ethyt iodide, 1-iodopropane, 1-

bromobutane, benzyl bromide, allyl bromide, 1,2-dibromopropane, and 1,5-dibromopentane

(Table 1, entries 1-4, 9-12) are readily displaced by 243 in tetrahydrofuran at room temperature to give 291-294 and 299-302, respectively, in reasonably good yields. With longer chain or

hindered primary halides, addition of hexamethylphosphoramide (HMPA) greatly accelerates

dialkylation. For example, 1 -iodohexane, 1 -iodooctane, 1 -bromo-3-methylbutane, and 1 -bromo-

3,3-dimethylbutane (Table 9, entries 5-8) are all readily displaced by 24 3 in

tetrahydrofuran/HMPA (5:1 by volume) solutions. Without HMPA, only monosubstituted sulfones

285 are obtained. ft.I

Figure 7. 13C NMR (200 MHz) of 1.1 -(Dilithio)-I -(benzenesulfonyl)-2-(trimethylsilyl)ethane (243) 3: i r W w

4 *

"T" tM in I4t 199

F i g u r e 6 . 1H NMR {200 MHz) of l,1-(Dilithio)-l-(benzenesulfonyl)-2-(trimethylsilyl)ethane (243) 122

The reaction temperature of a "lithio dianionic* solution greatly influences whether monoalkytation or dialkylation products result. Addition of an excess of an alkyl halide to a solution of 243 at -78°C with subsequent warming to room temperature even in the presence of

HMPA (20% by volume in tetrahydrofuran) result in only monoalkylated sulfones 285. However, reacting a solution of 243 which has been stirred for 1.5 h at 25°C with alkyl halides (w or w/o

HMPA) dialkylated products 2 44 predominate.

Fluoride Ion Eliminations ol 1,1-(Dlalkyl)>1>(benzenesulfonyl)-2-(trimethylsllyl)alkanes

(244).

Reactions of 244 with tetra-n-butylammonium fluoride (2.5 equivalents) in refluxing tetrahydrofuran result in fluoride>induced debenzenesulfonyltrimethylsilylation to afford symmetrical methylenealkanes (245, Equation 46). Dialkylated sulfones 295-299 are ail efficiently eliminated by fluoride ion to give methylenes 303-307 (Table 10) in good yields.

R S 02Ph TBAF, THF, 65°C R (246) R

246 244 123 Table 9. Dialkylation of 1 with Primary Alkyl Halldea

Entry Alkyl Halide Product Yield* (%)

1 c h 3i 291 R = CH3 90

2 c 2 h6i 292 R = C2 H5 55

3 /7-C3 H7 I 293 R = n-C3 H7 75

4 n-C^gBr 294 R = n-C4 H9 6 8

5 r>CeHi3lc 295 R = n C 6 Hi3 57

6 /7-CbH i 7Ic 296 R = n-C8 H 1 7 49

7 Me2 CHCH 2 CH 2 Brc 297 R = CH2 CH 2 CHMe2 69

8 Me3 CCH 2 CH 2 Brc 298 R = CH2 CH 2 CCMe3 80

9 PhCH2Br 299 R = CH2Ph 65

300 R = CH 2 H C = C H 2 1 0 H2 C = C H C H 2Br 84

1 1 Br(CH2 )3 Brd 301 R= — (CH2)3— 53

Br(CH2 )5 Brd 1 2 302 R=---- (CH2)5— 41

aFor general procedure, see text. *AII yields indicated refer to isolated analytically pure compounds characterized by 1H and 13C NMR, IR, and HRMS. Reactions were done in the presence of HMPA (2.0 ml_). dA solution of the 1 .eo-dihaloalkane in dry THF (10 mL) was added slowly over 1.5 h. 124

Table 10. Fluoride Ion Eliminations of DIsubstltuted Sulfones 244

Entry Sulfone Product Yield* (%)

1 296 303 R = n-CgHi3 75

2 296 304 R = n-CeHi7 76

3 297 305 R = (CH2 )2 CHMe2 81

4 296 306 R = (CH2 )2 CMe2 6 6

5 290 307 R = CH2Ph 80

aFor general procedure, see experimental. *AII yields indicated refer to isolated analytically pure compounds characterized by 1H and 13C NMR, IR and HRMS.

IV. Summary.

Reactions of 1 with two equivalents of n-butyllithium and various alkyl halides gave disubstituted sulfones 244 presumably through a,a-(dilithio)-1-(benzenesulfonyl)-2-

(trimethylsilyl)ethane (243) which were observed by deuterium labeling and spectroscopic

methods ( 1H and 13C NMR). Sulfones 244 were then effectively underwent 1 ,2-elimination to give symmetrical 1,1 -disubstituted alkenes 245.

V. Experimental Section.

Proton nuclear magnetic resonance spectra were recorded on Bruker AC-200, Bruker

AM-250 or Bruker AC-300 spectrometers and are reported in parts per million on the d scale when CDCI3 is denoted as the solvent with residual CHCI3 at d 7.26 as an internal reference. 125 1H-NMR spectra are reported as follows: chemical shifts [multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet), coupling constants in Hertz, integration, and interpretation],

1 3 C-NMR spectra were obtained on Bruker AC-200, Bruker AM-250, and Bruker AC-300 spectrometers. Carbon chemical shifts are reported in parts per million relative to the center line of the CDCI3 triplet (77.0 ppm) and are denoted as "C" (no protons attached), "CH" (one proton

attached), "CH 2 " (two protons attached) or CH 3 (three protons attached) as determined from the

DEPT pulse sequence. Infrared spectra were taken on a Perkin-Elmer 457 instrument. Mass spectra were recorded on a Kratos MS-30 instrument at an ionization energy of 70 eV. Solvents and reagents were dried and purified prior to use when deemed necessary: tetrahydrofuran was predried over potassium hydroxide and distilled from lithium aluminum hydride, diethyl ether was distilled from benzophenone ketyl, and methylene chloride was distilled from calcium hydride. All reactions were conducted under argon. Analytical thin-tayer chromatography was performed with

EM Laboratories 0.25 mm thick precoated silica gel 60F-254 plates. Elemental analyses were performed by Micro Analyses, Inc., Wilmington, DE. or Atlantic Microlab, Inc., Norcross, GA.

Preparation of 1-

A solution of trimethyl(vinyl)silane (52.0 g, 0.52 mol) and thiophenol (90.0 g, 0.80 mol) with a catalytic amount of AIBN (100 mg) was heated under argon to 110°C for 1 h. The mixture was cooled, diluted with diethyl ether (200 mL), washed with 1 N aqueous potassium hydroxide (2 X

100 mL) and brine (2 X 100 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to afford

289 (91.6 g, 84%) as colorless liquid: IR (neat) 3060, 2950, 1585, 1480, 1440, 1250, 1160, 126

1090, 1070, 1025, 1010, 860, 840, 740, 690 cm'1; 1H NMR (CDCI 3 , 250 MHz) 8 0.07 (s, 9H,

SiMe3 ), 0.93-1.0 (m, 2 H, SiCH2), 2.95-3.02 (m, 2 H, SCH2 ), 7.16-7.35

NMR {CDCI3 , 50 MHz) 8 -1.80 (CH 3 ), 16.81 (CH2), 29.42 (CH 2 ), 125.60 (CH), 128.76 (CH),

128.87 (CH), 137.20 (CH); exact mass calcd for C 1 1 H-iaSiS m/e 210.0898, found m/e

210.0894.

Preparation of 1 -(Benzenesulf ony l)-2-(trimethylsllyl)ethane (1 ).11 • 12

Me3 s , ^ S° 2Ph

Hydrogen peroxide (30%; 8.5 g, 0.250 mol) was added to 289 (30.0 g, 0.143 mol) in glacial acetic acid (65 mL). The two-layered mixture was heated to 60°C, and additional hydrogen peroxide (30%; 14.0 g, 0.45 mol) was added slowly. The mixture was then warmed to 100°C for

2 h, cooled, and concentrated in vacuo to remove most of the acetic acid and water. The residue was then diluted with diethyl ether (100 mL), washed with saturated aqueous sodium bicarbonate (100 mL) and brine (100 mL), dried (MgS0 4 ), filtered, and evaporated to give 1 as a colorless oil (27.6 g, 80%) which crystallized to a white solid on standing: mp 50-51 °C (lit

52°C); IR (KBr pellet) ; 1HNMR (CDCI3 , 200 MHz) 6 -0.01 (s, 9H, SiMe 3 ), 0.87-0.96 (m, 2H,

SiCH2 ). 2.94-3.03 (m, 2 H, S 0 2 CH2), 7.53-7.65 (m, 3H, aromatic), 7.88-7.92 (m, 2H, aromatic);

13C NMR (CDCI3 , 50 MHz) 8 -2.09 (CH3), 9.03 (CH 2 ), 52.67 (CH 2 ), 128.18 (CH), 129.17

(CH). 133.50 (CH), 133.70 (C); exact mass calcd for CsH-oSi (M+-S 0 2 Ph) m/e 101.0787, found m/e 101.0791. 127 1-(Benzenesulf onyl)-1,1-(dideutero)-2-(trimethyl«ilyl)ethane (290).

D Me3Si^ f - S° * Ph D

To a solution of 1 (125 mg, 0.516 mmol) in anhydrous THF (10 mL) was syringed in slowly n- butyllithium (0.66 mL, 1.19 mmol, 1.80 M in hexane) at -7 8 °C under argon. The colorless solution immediately turned yellow and was stirred 20 min at -78° C before being quenched with deuterium oxide (21 mg, 1.09 mmol). The colorless mixture was diluted with diethyl ether (20 mL), washed with brine (2X10 mL), dried (MgS0 4 ), filtered, and concentrated in vacuo to give a colorless residue (173 mg) which was chromatographed (silica gel; ethyl acetate.hexanes, 1:5) to yield 290 (93 mg, 74%) as a colorless oil: IR (neat) 2950, 1585, 1445, 1305, 1250, 1195,

1150,1085,1025, 860,760,730,690,610 cm-1; 1H NMR (CDCI 3 , 200 MHz) 5 -0.04 (s, 9H,

Si Me 3 ), 0.86-0.91 (m, 2H, SiCH 2 ), 7.49-7.62

13C NMR (CDCI3 , 50 MHz) 6 -2.18 (CH 3 ), 8.80 (CH 2 ), 52.22 (triplet center), 128.06 (CH),

128.96 (CH), 133.43 (CH), 138.55 (C); exact mass calcd for C sH itSiD 2 (M+ -S0 2 Ph) m/e

103.0912, found m/e 103.0926.

General Procedure (A) for Dlalkylations of 1-(Benzenesulfonyl)-2-{trimethylsilyl)ethane (1):

2-(Benzenesulfonyl)-2-< methyl)-1 -(trimethylsilyl)propane (291).

c h 3 128

To a solution of 1 (163 mg, 0.672 mmol) in anhydrous THF (10 mL) was slowly syringed n- butyllithium (0.77 mL, 1.55 mmol, 2.0 M in hexane) at -78°C under argon. After 20 min, the yellow dilithio anionic solution was warmed to room temperature for 1.5 h before methyl iodide

(954 mg, 6.72 mmol) was added. After an additional hour, the yellow mixture was diluted with diethyl ether (20 mL), washed with brine (2X10 mL), dried (MgSCU), filtered, and concentrated in vacuo to yield a brown oil (305 mg) which was chromatographed (silica gel; ethyl acetate:hexanes, 1:10) to afford 291 (163 mg, 90%) as a yellow oil: IR (neat) 2955,1585, 1300,

1250, 1230, 1150, 1115, 1075, 1025, 950, 845, 760, 725, 690, 650 cm-1; 1 H NMR (CDCI3 , 200

MHz) 8 0.06 (s, 9H, SiMe 3 ), 1.22 (s, 2H, SiCH 2 ). 133 (s, 6 H, 2 CH3 ), 7..48-7.67 (m, 3H, aromatic), 7.83-7.88 (m, 2H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 8 0.61 (CH 3 ), 15.68

(CH2 ). 23.00 (CH3 ), 63.73 (C). 128.52 (CH), 130.68 (CH), 133.39 (CH), 134.96 (C); exact mass calcd forCyHiySi (M+-S 0 2 Ph) m/e 129.1100, found m/e 129.1115.

3-(Benzenesulfonyl)-3-(trimethylsilylmethyl) (292):

Me3Si

General procedure A using 1 (870 mg. 3.59 mmol), n-butyllithium (5.0 mL, 9.0 mmol, 1.8 M in hexanes), and iodoethane (5.6 g, 35.9 mmol) gave 292 (592 mg, 55%) as a colorless oil: IR

(neat) 2950, 1585, 1445, 1285, 1250, 1140, 1070, 915, 860, 840, 760. 730, 690, 635, 605 cm'1;

1H NMR (CDCI3 , 200 MHz) 8 0.12 (s, 9H, SiMe 3 ), 1.04 (t, J * 7.4 Hz, 6 H, 2 CH3 ), 1.25 (S, 2H,

SiCH2 ), 1.46-1.89 (m. 4H, 2 CH 2 ). 7.49-7.63 (m, 3H. aromatic), 7.85-7.89 (m, 2 H, aromatic); 129

13C NMR (CDCI3 , 50 MHz) 5 0.83 (CH 3 ), 9.10 (CH3), 19.14 {CH 2 ), 28.40 {CH2 ), 70.36 (C).

128.55 (CH), 129.95 (CH). 133.16 (CH), 136.88 (C); exact mass calcd for C 9 H2 1 S (M+-

SC>2 Ph) m/e 157.1412, found m/e 157.1425. Anal Calcd for C i5H26S02Si: C, 60.35; H.

8.78. Found: C, 60.53; H, 8.85.

4-(Benzenesutfonyl}-4-(trimethylsilylm«thyl)heptane (293):

n-C3 H7

M 6 3 S 1

Following general procedure A, 1 (117 mg, 0.483 mmol), n-butyllithium (0.67 mL, 1.20 mmol, 1.8

M in hexanes), and 1- iodopropane (411 mg, 2.42 mmol) yielded 293 (118 mg, 75%) as a colorless oil: IR (neat) 2960, 1580, 1465, 1445, 1290, 1140, 1080, 910, 840, 725, 690, 640 cm*

1; 1 H NMR (CDCI3 , 250 MHz) 5 0.09 (s, 9H, SiMe 3 ), 0.83 (t, J = 6 . 8 Hz, 6 H, 2CH3), 1.23 (s,

2 H, SiCH2 ), 1.36-1.77 (m, 8 H, 4CH2), 7.49-7.61 (m, 3H, aromatic), 7.82-7.89 (m, 2 H, aromatic);

13C NMR (CDCI3 , 63 MHz) S 0.84 (CH 3 ), 14.45 (CH 3 ), 17.55 (CH2), 20.53 (CH 2 ), 38.37

(CH2), 70.44 (C), 128.57 (CH), 129.97 (CH), 133.19 (CH). 137.10 (C); exact mass calcd for

C iiH 2 5 Si(M+ -SC>2 Ph) m/e 185.1725, found m/e 185.1713. Anal Calcd for C 1 7 H3 0 SO2 Si: C,

62.52; H, 9.26. Found: C, 62.60; H, 9.26. 130 5-(Benzenesulfonyl)-5-(trimethylsilylmethyl) (294):

n-CdHo

Following general procedure A reactions of 1 (135 mg, 0.557 mmol), n-butyllithium (0.77 mL,

1.39 mmol, 1.0 M in hexanes), and 1- bromobutane (381 mg, 2.79 mmol) gave 294 (135 mg,

6 8 %) as a colorless Oil: IR (neat) 2955, 1585, 1470, 1445, 1295, 1250, 1140, 1125, 1080, 915,

845,760,725, 690,640, 610 cm'1; 1H NMR (CDCI 3 , 200 MHz) 6 0.08 (S, 9H, SiMe 3 ), 0.86

(t, J » 7.0 Hz, 6 H, 2 CH 3 ), 1.11-1.79 (m, 14H, 7 CH2 ), 7.46-7.65 (m, 3H, aromatic), 7.80-7.85 (m,

2H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 5 0.92 (CH 3 ), 13.88 (CH 3 ), 20.58 (CH2), 23.32

(CH2 ), 26.32 (CH2 ), 35.96 (CH2 ), 70.57 (C), 128.58 (CH), 130.05 (CH), 130.23 (CH), 137.03 (C); exact mass calcd for C i 3 H2 gSi (M+ -SO2 Ph) m/e 213.2039, found m/e 213.2043.

7-(Benzenesulfonyl)-7-(trimethylsilylmethyl)trid»cane(295):

n-C«H

Use of general procedure A with 1 (620 mg, 2.56 mmol), n-butyllithium (3.6 mL, 6.59 mmol, 1.8

M in hexanes), and 1- iodohexane (2.7 g, 12.8 mmol) led to 295 (593 mg, 57%) as a colorless oil:

IR (neat) 3070, 2955, 1585, 1465, 1445, 1380, 1365, 1295, 1250, 1180, 1140, 1080, 1025, 1000, 131

910, 845, 790, 610, 555 cm'1; 1 H NMR (CDCI3 , 200 MHz) 5 0.09 (s, 9H, SiMe 3 ), 0.87 (t, J =

6.9 Hz, 6 H, 2 CH3 ), 1.15-1.82

24.21 (CH2), 29.96 (CH2), 31.60 (CH2), 36.28

133.22 (CH), 137.12 (C); exact mass calcd for C-| 7 H3 7 Si (M+ - S 0 2 Ph) m/e 269.2665, found m/e 269.2652.

9-(Benzenesulfonyl)-9-(trimethylsilylmethyl)heptadecane (296):

n-CftHi7

Upon following general procedure A, 1 (720 mg, 2.97 mmol), n-butyllithium (4.1 mL, 7.43 mmol,

1. 8 M in hexanes), and 1 - iodooctane (2.85 g, 1 1 .9 mmol) gave 296 (680 mg, 49%) as a colorless oil: IR (neat) 2945,1560,1450, 1390,1345.1270,1190.1100,970,895,805,750,710, 660,

620, 595, 570 cm’ 1; 1H NMR (CDCI 3 , 300 MHz) 8 0.11 (s, 9H, SiMe 3 ), 0.89 (t, J = 6 . 8 Hz, 6 H,

2 CH 3 ), 1.18-1.79 (m. 30 H, 15CH2), 7.50-7.66 (m, 3H, aromatic), 7.84-7.87 (m, 2H, aromatic);

13C NMR (CDCI3 , 63 MHz) 8 0.95 (CH 3 ), 14.05 (CH3 ), 20.75 (CH2), 22.61 (CH2), 24.24 (CH2),

29.22 (CH2 ), 29.35 (CH2), 30.28 (CH2), 31.79 (CH2), 36.26 (CH2), 70.72 (C), 128.57 (CH),

130.10 (CH), 133.18 (CH). 137.28 (C); exact mass calcd for C 2 iH 4 sSi (M+-S0 2 Ph) m/e

325.3291, found m/e 325,3281. Anal Calcd for C 2 7 H5 oS0 2 Si: C, 69.47; H, 10.79. Found: C.

69.31; H, 10.83. 132 5-(Benzenesulfonyl)>2,8-(dimethyl)>5-{trimethyl8llylmethyl)nonane (297):

(C H ^ C H M e 2 Me3S i ^ V p 2Ph

(CH2 )2 CHMe2

Following general procedure A with 1 (650 mg, 2.68 mmol), n-butyllithium (3.7 mL, 6.71 mmol,

1.8 M in hexanes) and 1-bromo-3-methylbutane (2.0 g, 13.4 mmol), 297 (710 mg, 69%) was

obtained as a colorless oil: IR (neat) 3070, 2955, 1585, 1470, 1445, 1420, 1385, 1370, 1295,

1250, 1215, 1145, 1080, 1025, 1000, 985, 915, 845, 790, 760, 725,690, 640, 610, 570 cm ' 1 ; 1H

NMR (CDCI3 , 300 MHz) 6 0.11 (s. 9H, SiMe 3 ), 0.86 (t, J = 6.2 Hz, 12H, 4 CH 3 ), 1.23 (s, 2 H,

SiCH2 ). 1.21-1.81 (m, 10 H, 2CH, 4CH2), 7.50-7.65 (m, 3H, aromatic), 7.84-7.87 (m, 2 H,

aromatic); 13C NMR (CDCI 3 , 75 MHz) 6 1.08 (CH 3 ), 20.94 (CH 2 ), 22.32 (CH3 ), 28.91 (CH 2 ),

32.85 (CH 2 ), 34.15 (CH), 70.69 (C), 128.55 (CH), 130.21 (CH), 133.24 (CH), 137.28 (C); exact

mass calcd for C isH 3 3 Si (M+ -S0 2 Ph) m/e 241.2351, found m/e 241.2373. Anal Calcd for

C2lH38S02Si: C, 65.91; H, 10.01. Found: C, 65.84; H, 9.92.

5-

(CH2 )2 CMe3 ^ O ^ S 0 2Ph Me3Sr (CH2)2CMe3 133

General procedure A using 1 (110 mg, 0.454 mmol), n-butyllithium (0.63 mL, 1.13 mmol, 1 . 8 M in hexanes), and 1- bromo-3,3-dimethylbutane (375 mg, 2.27 mmol) gave 296 (149 mg, 80%) as a colorless Oil: IR (neat) 3070, 2955, 1585, 1445, 1420, 1395, 1365, 1290, 1250, 1180, 1135,

1085, 1065, 1025, 1000, 980, 910, 840, 760, 735, 690, 640, 610, 570 cm'1 ; 1 H NMR (CDCI3 ,

200 MHz) 5 0.11 (s, 9H, SiM 6 3 ), 0.85 (s, 18H, 2 CMe3 ), 1.18 (s, 2 H, S1CH2 ). 1.20-1.75 (m, 8 H.

4 CH 2 ). 7.48-7.63 (m, 3H, aromatic). 7.84-7.89 (m, 2H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 5

1.47 (CH 3 ), 22.35 (CH2 ), 29.51 (CH3), 30.53 (CH 2 ), 30.57 (CH2 ), 37.38 (C). 70.78 (C), 128.70

(CH), 130.56 (CH), 133.49 (CH), 137.49 (C); exact mass calcd for C i 7 H3 7 Si (M+-SC>2 Ph) m/e

269.2664, found m/e 269.2726. Anal Calcd for C23H42S02Si: C, 67.26; H, 10.31. Found: C,

66.56; H, 10.15.

2-(Benzenesulfonyl)-2-{trimethylsilylmethyl)-1,3-{diphenyl)propane (299):

CHoPh /\US 0 2Ph Me3s r CH2Ph

Following general procedure A, 1 (651 mg, 2.69 mmol), n-butyllithium (3.73 mL, 6.72 mmol, 1.8

M in hexanes), and benzyl bromide (1.01 g, 5.92 mmol) resulted in 299 (741 mg, 65%) as a white solid: mp: 124-125°C; IR (KBr pellet) 3060, 3030, 2950, 1580, 1495, 1455, 1445, 1300, 1250,

1135,1080,910,840,735,690,640,605 cm'1; 1H NMR (CDCIs, 200 MHz) 6 0.21 (s, 9H,

SiMe3 ), 1.15 (s, 2 H, SiCH2 ), 3.12 (d, J = 14.2 Hz, 1 H, CH), 3.23 (d, J = 14.1 Hz, 1 H, CH), 7.11-

7.58 (m, 15H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 5 1.20 (CH3 ), 23.13 (CH2 ), 41.00 (CH2 ),

72.06 (C), 126.94 (CH), 128.03 (CH), 128.94 (CH), 130.56 (CH), 131.44 (CH), 132.72 (CH), 134

135.74 (C), 137.51 2 Ph) m/e 281.1725, found m/e 281.1730. Anal Calcd for C25H3oS02Si: C, 71.04; H, 7.15. Found: C, 70.31, H. 7.38.

4>(Benzenesulfony l)-4-(trimethylsilylmftthyl)-1 ,6-heptadtone (300):

c h 2 c h = c h 2 M e 3S i^ S°2Ph

ch 2 c h = c h 2

Use of general procedure A with 1 (780 mg, 3.22 mmol), n-butyllithium (4.5 mL, 8.04 mmol, 1 . 8

M in hexanes), and 1- bromobutane (3.09 g, 32.7 mmol) yielded 3 0 0 (870 mg, 84%) as a colorless oil: IR (neat) 2950, 1640, 1585, 1445, 1300, 1250, 1140, 1080, 1 0 0 0 , 920, 840, 760,

730, 690, 640 cm'1; 1H NMR (CDCI 3 , 200 MHz) 5 0.13 (S, 9H, Si Me 3 ), 1 . 2 1 (s, 2 H, SiCH2 ),

2.27-2.58 (m. 4H, 2 CH2 ), 4.98-5.13 (m, 4H, vinyl), 5.81-6.01 (m, 2H, vinyl), 7.47-7.67 (m, 3H, aromatic), 7.84-7.89 (m, 2 H, aromatic); 13C NMR (CDCI 3 , 50 MHz) S 1 .11 (CH3 ), 20.29 (CH 2 ),

40.04 (CH2 ), 69.34 (C), 118.78 (CH 2 ), 128.58 (CH), 130.51 (CH), 132.79 (CH), 133.47 (CH),

136.36 (C); exact mass calcd for C n H 2 iSi (M+-SC>2 Ph) m/e 181.1413, found m/e 181.1417.

Anal Calcd for Ci7H26S02Si: C, 63.31; H, 8.12. Found: C, 63.23; H, 8.13.

1-(Benzenesulfonyl)-2-(trimethylsilylmethyl) (301):

MeaSi 135 Following general procedure A reactions of1 (300 mg, 1.24 mmol), n-butyllithium (2.6 mL, 3.2 mmol, 1.2 M in hexanes), and 1,3-dibromopropane (275 mg, 1.36 mmol) in dry THF (10 mL) with addition time of 1.5 h gave 301 (142 mg, 41%) as a colorless oil: IR (neat) 3065, 2950, 2900,

1585, 1445, 1300, 1250, 1140, 1085, 920, 840, 760, 730, 690 cm*1; 1H NMR (CDCI 3 , 200

MHz) 6 0.10 (s, 9H, Si Me 3 ), 1.03 (s, 2 H, SiCH2 ), 1.83-2.04 (m, 4H. 2 CH2 ), 2.74-2.87 (m, 2H,

2 CH 2 ), 7.47-7.61 (m, 3H, aromatic), 7.83-7.87 (m, 2H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 5

-3.09 (CH 3 ), 14.23(CH2), 22.84 (CH2), 27.91 (CH2), 65.47 (C), 128.57 (CH), 129.90 (CH),

133.28 (CH), 135.63 (C); exact mass calcd for C i 4 H2 2 0 2 SSi m/e 282.1110, found m/e

282.1080.

1-(Benzenesulf onyl)-2-(trlmethylsilylmethyl)cyclohexane (302):

SO ,Fh Me Si

Use general procedure A with 1 (300 mg, 1.24 mmol), n-butyllithium (2.6 mL, 3.2 mmol, 1 . 2 M in hexanes), and 1,5-dibromopentane (275 mg, mmol) in dry THF (10 mL) with addition time of 1.5 h led to 302 (202 mg. 53%) as a colorless oil: IR (neat) 3065, 2950, 2870, 1585, 1445, 1300,

1250, 1135, 1085, 1010, 860, 740, 690, 605 cm*1; 1H NMR (CDCI 3 , 200 MHz) 8 0.15 (s, 9H,

Si Mes), 1.11 (s, 2H, SiCH2 ), 1.40-1.77 (m, 1 0 H, 5 CH2 ), 7.51-7.61 (m, 3H, aromatic), 7.81-7.86

(m, 2H, aromatic); 13C NMR (CDCI 3 , 50 MHz) 8 0.99 (CH3), 2 0 . 1 0 (CH2). 21.38 (CH2), 24.84

(CH2 ). 32.02 (CH2 ), 66.53 (C), 128.43 (CH), 130.68 (CH), 133.18 (CH), 135.72 (C): exact mass calcd for C ieH 2 6 0 2 SSi m/e 310.1423, found m/e 310.1462. 136

General Procedure (B) for Fluoride-lon Eliminations of 1,1-(Dialkyl}-1-(benzenesulfonyl)-2-

(trimethylsilyl)alkanes (244): 2>Hexy 1-1 - (303).

n-CsH^

To a solution of 295 (530 mg, 1.29 mmol) in anhydrous THF (10 mL) was added tetra-n- butylammonium fluoride (3.3 mL, 3.30 mmol, 1.0 M in THF). The light brown mixture was refluxed for 1 h, cooled, diluted with diethyl ether (20 mL), washed with brine (3X10 mL), dried

(MgSCU), filtered, and concentrated in vacuo to a brown oil which was passed through a silica gel column (10 cm, hexanes) to afford 303 (191 mg, 75%) as a colorless oil: IR (neat) 3080,

2955, 2925, 2855, 1645, 1465, 1380,1250, 1060, 890, 845, 790 cm’1; 1H NMR (CDCI 3 , 200

MHz) 5 0.89 (t. J = 6,5 Hz, 6 H, 2 CH 3 ), 1.28-1.44 (m, 16H, 8 CH 2 ), 2 00 (t, J = 7.3 Hz, 4H, 2 CH 2 ),

4.69 (s, 2 H, vinyl): 13C NMR (CDCI 3 , 50 MHz) 5 14.08 (CH 3 ), 22.67 (CH2 ), 27.80 {CH 2 ),

29.15 (CH 2 ), 31.83 (CH 2 ), 36.09 {CH 2 ), 108.41 (CH 2 ), 150.14 (C); exact mass calcd for

C 1 4 H2 8 "vfe 196.2191, found m/e 196.2199.

2-Octyl-1 - (304):

rt-CsHi7

>T-CbH i 7 137

General procedure B using 296 (550 mg, 1.18 mmol) and tetra-n-butylammonium fluoride (3.0

mL, 3.0 mmol, 1 . 0 M in THF) gave 304 (225 mg, 76%) as a colorless oil: IR (neat) 3070, 2925,

2855, 1645, 1465, 1380, 1250, 1150, 1060, 910, 890, 840, 790, 735, 580 Cm'1; 1 H NMR

(CDCI3 , 250 MHz) 5 0.90 (t, J = 6 . 6 Hz. 6 H, 2 CH3 ), 1.29-1.45 (m, 24H,12CH2), 2.00 (t, J = 7.5

Hz. 4H, 2CH2), 4.70 (s, 2H, vinyl); 13C NMR (CDCI 3 , 63 MHz) 6 14.10 (CH3), 22.70 (CH 2 ).

27.88 (CH 2 ), 29.34 (CH 2 ), 29.56 (CH 2 ), 31.93 (CH 2 ), 36.12 (CH 2 ), 108.40 (CH2 ), 150.32 (C); exact mass calcd for C 1 8 H3 6 rr^e 252.2817, found m/e 252.2773.

2-(3-methylbutyl)-5-methyl-1 -hexene (305):

(CH2 )2 CHMe2

'"(CH2 )2 CHMe2

Following general procedure B, reaction of 297 (630 mg, 1.65 mmol) and tetra-n-butylammonium fluoride (4.1 mL, 4.1 mmol, 1.0 M in THF) gave 305 (225 mg, 81%) as a colorless oil: IR (neat)

3070, 2955, 2870, 1645, 1470, 1385, 1365, 1335, 1255, 1170, 1125, 1060, 885, 840, 790 cm'1 ;

1H NMR (CDCI3 , 200 MHz) 8 0.90 (d, J = 6.5 Hz, 12H, 4CH 3 ), 1.25-1.36 (m, 4H, 2CH2), 145-

1.61 (m, 2H, 2 CH), 2.01 (t, J = 8.0 Hz, 4H, 2CH2), 4.70 (s, 2H, vinyl); 13C NMR (CDCI 3 , 50

MHz) 8 22.61 (CH3 ), 27.86 (CH2 ), 33.96 (CH), 37.15 (CH2), 108.20 (CH2), 150.67 (C); exact mass calcd for C i 2 H2 4 m/e 168.1878, found m/e 168.1855. 138 2-(3,3-dimethylbutyl)-5t5-dimethyM -hexane (306):

(CH2 )2 CMe3

(CH2 )2 CMe3

Upon following general procedure B, 298 (210 mg, 0.512 mmol) and tetra-n-butylammonium

fluoride (1.3 mL, 1.3 mmol, 1.0 M in THF) gave 306 ( 6 6 mg, 6 6 %) as a colorless oil: IR (neat)

3070, 2955, 2865, 1645, 1475, 1390, 1365, 1310, 1250, 885 cm’ 1; 1 H NMR (CDCI3 , 200 MHz)

5 0.90 (s. 18H, 6 CH 3 ), 1.26-1.35 (m, 4H, 2 CH2 ), 1.93-2.01 (m, 4H. 2 CH2 ), 4.68 (s, 2 H, vinyl);

13c NMR (CDCI 3 , 50 MHz) 5 29.34 (CH 3 ), 30.25 (C), 31.31 (CH 2 ). 42.43 (CH 2 ). 107.58

(CH2 ), 151.94 (C); exact mass calcd for C 1 4 H2 8 mte 196.2190, found m/e 196.2183.

1,1 -B is(benzyl) (307):

CH2Ph

CH2Ph

Use of general procedure B with 299 (212 mg, 0.502 mmol) and tetra-n-butylammonium fluoride

(1.2 mL, 1.2 mmol, 1.0 M in THF) led to 307 (84 mg, 80%) as a colorless oil: ir (neat) 3080,

3060, 3025, 2905, 1645, 1600, 1495, 1450, 1430, 1075, 1030, 895, 750, 700 cm'1; 1H NMR

(CDCI3 , 200 MHz) 5 3.33 (s, 4 H. 2 CH2 ). 4.90 (s, 2H, vinyl), 7.19-7.39 (m, 10H, aromatic); 13C

NMR (CDCI3 , 50 MHz) 5 42.12 (CH2 ), 113.35 (CH2 ), 126.09 (CH), 128.27 (CH), 129.07 (CH),

139.45 (C), 148.28 (C); exact mass calcd for C 1 6 H 1 6 m/e 208.1252, found m/e 208.1264. PLEASE NOTE

Page(s) not included with original material ana unavaiable from author or university. Filmed as rsoeived.

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