Rearrangement and Fragmentation Reactions of Cyclopropylmethylidenes

This dissertation has been 65—5677 microfilmed exactly as received

SMITH, James Allbee, 1937- REARRANGEMENT AND FRAGMENTATION REACTIONS OF CYCLOPROPYLMETHYLIDENES.

The Ohio State University, Ph.D., 1964 Chemistry, organic

University Microfilms, Inc., Ann Arbor, Michigan REARRANGEMENT AND FRAGMENTATION REACTIONS OP CYCLOPROPYLMETHYLIDENES

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

By James Allhee Smith, B.S. In Chemistry

******

The Ohio State University 1964

Adviser Department of Chemistry ACKNOWLEDGMENTS

I am Indebted to Professor Harold Shechter for suggesting this problem and for his guidance and instruo tion. I also wish to acknowledge the assistance of Dr. T. Page, Battelie Memorial Institute, in the inter pretation of some of the nuclear magnetic resonance spectra. I am grateful for the financial aid given by Union Carbide Corporation, Du Pont Company, and the National Science Foundation,

ii VITA

October 20, 1937 Born - Detroit, Michigan 1955 Graduated from Pontiac High School, Pontiac, Michigan

1959 B.S. in Chemistry, University of Michigan, Ann Arbor, Michigan 1959-1960 Teaching assistant. Department of Chemistry, The Ohio State University, Columbus, Ohio

1961-1963 National Science Foundation Cooperative Fellow, Department of Chemistry, The Ohio State University, Columbus, Ohio 1963-1964 Union Carbide Corporation Fellow, Department of Chemistry, The Ohio State University, Columbus, Ohio

iii CONTENTS Page

I. INTRODUCTION AND HISTORICAL...... 1 II. SUMMARY ...... II III. DISCUSSION...... 13 IV. EXPERIMENTAL ...... 59 GENERAL PROCEDURES AND TECHNIQUES...... 59 Melting points...... 59 Boiling points...... 59 Elemental analysis...... 59 Infrared spectra...... 59 Ultraviolet spectra...... 50 Near-Infrared spectra...... 60 Nuclear magnetic resonance spectra... 60 Gas chromatography...... 60 Preparative gas chromatography...... 62 INTERMEDIATES...... 62

p-Toluenesulfony1 hydrazlde (tosyl hydrazlde)...... 62 Trlmethylsulfoxonlum Iodide...... 63 1 -Phenyl -1 -cyanocy c lopr opane...... 63 Cyclopropyl ketone...... «...... 63 2,2,4,4-Tetramethylcyclohutanone 63 2,2-Dlmethylcyclopropyl methyl ketone ...... 64 Phenyl 1-phenylcyclopropyl ketone.... 65 1-Phenylcyclopropanecarhoxaldehyde... 66 Blcyclo [4.1.0] -2-heptanone...... 67 o(,2-Dlmethylcyclopropanemethanol 68 Methyl 2-methylcyclopropyl ketone.... 69 Cyclopropanecarboxaldehyde ..... 71 1-Phenylcyclopropanecarboxaldehyde-d. 71 Cyc lopr opane carboxaldehyde-d...... 72 Tosy Ihydrazone s ...... 73 Cyclopropyl methyl ketone tosy Ihydrazone...... 73 Cyclopropyl ketone tosylhydrazone...... 73 Iv CONTENTS (contd.)

Page Cyclopropyl phenyl ketone tosyIhydrazone ...... 73 1-Phenylcyclopropanec arhoxal- dehyde tosyIhydrazone...... 74 2,2-Dlmethylcyclopropyl methyl ketone tosyIhydrazone...... 75 2,2,4,4-TetramethyIcyclo- hutanone tosyIhydrazone .. .. 75 BIcyclo[4.1.0]-2-heptanone tosyIhydrazone ...... 76 Methyl 2-methylcyclopropyl ketone tosyIhydrazone...... 76 Cyclopropanecarboxaldehyde tosyIhydrazone ...... 77 Cyclopropanecarboxaldehyde-d tosyIhydrazone ...... 77 1-Phenylcyclopropanecarbox aldehyde -d tosyIhydrazone .. 77 Phenyl 1-phenylcyclopropyl ketone tosylhydrazone ...... 78 Sodium salts of tosylhydrazones: general procedures ...... 78 Lithium salt of cyclopropanecarbox aldehyde-d tosylhydrazone .. 79 PRELIMINARY DECOMPOSITIONS ...... 79 Thermal decomposition of cyclopropyl ketone tosylhydrazone In N-methyIpyrrolIdone with sodium methoxlde...... 79 Thermal decomposition of cyclopropyl ketone tosylhydrazone with sodium methoxlde In other solvents...... 8l Thermal decomposition of the sodium salt of cyclopropyl ketone tosylhydrazone at atmospheric pressure ...... 82 Thermal decomposition of the silver salt of cyclopropyl ketone tosylhydrazone at atmospheric pressure ...... 83 Thermal decomposition of the silver salt of cyclopropyl ketone tosylhydrazone In dlglyme .... 83 CONTENTS (contd.) Page Ultraviolet irradiation of the sodium salt of cyclopropyl ketone tosylhydrazone in several media 84 VACUUM PYROLYSES OP SODIUM SALTS OP TOSYLHYDRAZONES ...... 84 General techniques...... 84 Vacuum pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone...... 85 Reactions of 1-cyclopropyl- cyclohutene8Y Hydroboration ...... 87 Diimide reduction...... 87 Brown catalytic hydrogenation 88 Permanganate oxidation ...... 89 Vacuum pyrolysis of the sodium salt of cyclopropanecarbox aldehyde tosylhydrazonô...... 90 Pyrolysis of the sodium salt of cyclopropanecarboxaldehyde tosylhydrazone at atmospheric pressure 9^ Thermal decomposition of Cyclo propane carboxaldehyde tosyl hydrazone in diethyl Carbitol .. 91 Thermal decomposition of cyclo propanecarboxaldehyde tosyl hydrazone in diethyl Carbitol with insufficient sodium m e t h o X i d e 9^ Thermal decomposition of cyclo propanecarboxaldehyde tosyl hydrazone in diethyl Carbitol with excess sodium methoxide.... 93 Thermal decomposition of the sodium salt of cyclopropane carboxaldehyde tosylhydrazone in diethyl Carbitol ...... 9^ Thermal decomposition of the sodium salt of cyclopropane carboxaldehyde tosylhydrazone in diethyl Carbitol with 10^ ethylene glycol ...... 94

Vi CONTENTS (contd.) Page Thermal decomposition of the sodium salt of cyclopropane carboxaldehyde tosylhydrazone In diethyl Carbitol with 1.25J^ water ... «...... 95 Thermal decomposition of the sodium salt of cyclopropane carboxaldehyde tosylhydrazone In ethylene glycol...... 95 Vacuum pyrolysis of the lithium salt of cyclopropanecarbox aldehyde -d tosylhydrazone...... 96 Vacuum pyrolysis of the sodium salt of 1-phenylcyclopropane carboxaldehyde tosylhydrazone ... 96 Vacuum pyrolysis of the sodium salt of 1-phenylcyclopropane carboxaldehyde -d tosylhydrazone.. 97 Vacuum pyrolysis of the sodium salt of 2,2-dimethyIcyclopropyl methyl ketone tosylhydrazone .... 98 Vacuum pyrolysis of the sodium salt of methyl 2-methylcyclopropyl ketone tosylhydrazone...... 99 Vacuum pyrolysis of the sodium salt of bIcyclo[4.1.0]-2-heptanone tosylhydrazone...... 101 Vacuum pyrolysis of the sodium salt of cyclopropyl methyl ketone tosylhydrazone ...... 103 Vacuum pyrolysis of the sodium salt of cyclopropyl phenyl ketone tosylhydrazone ...... 104 Pyrolysis of cyclopropyIdlazo- phenylmethane...... 104 Vacuum pyrolysis of the sodium salt of phenyl 1-phenylcyclopropyl ketone tosylhydrazone...... 105 Pyrolysis of dlazonhenyl(l- phenylcyclopropyl)methane ..... 106 Vacuum pyrolysis of the sodium salt of 2,2,4,4-tetramethylcyclobutanone tosylydrazone ...... 107 High dilution vapor phase de composition of 2,2,4,4-tetra- methyldlazocyclobutane ...... 107

vll CONTENTS (contd.) Page

STANDARDS...... 109 Dlcyclopropylcarblnol...... 109 Dicyclopropylmethylmethyl ether .... 109 REAGENTS AND SOLVENTS...... 110

APPENDIX I Tables...... 112 II Infrared Spectra...... 124 III Nuclear Magnetic Resoneuice Spectra...... 137 IV Ultraviolet Spectra...... 162 V Near-Infrared Spectrum...... I65 VI Gas Chromâtogramst ...... l6?

viii TABLES Table Page 1 Vacuum pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone...... 113 2 Vacuum pyrolysis of the sodium salt of cyclopropanecarboxaldehyde tosylhydrazone .. 114 3 Pyrolysis of the sodium salt of cyclopro panecarboxaldehyde tosylhydrazone at atmospheric pressure...... 1 1 5 4 Decomposition of cyclopropanecarboxal dehyde tosylhydgazone In diethyl Oarbltol at loO ##@###*#####*####4 o • • • • .. 116 5 Decomposition of the sodium salt of cyclopropanecarboxaldehyde tosylhydra zone at 1 8 0..... ###### .. 117 6 Vacuum pyrolysis of the sodium salt of 1-phenylcyclopropanecarboxaldehyde tosylhydrazone ••••••••••••••••••••••••• .. 118 7 Vacuum pyrolysis of the sodium salt of 2,2,-dimethyIcyclopropyl methyl ketone tosylhydrazone «••••«•••••*••••••••••••« ..1 1 9 8 Vacuum pyrolysis of the sodium salt of methyl 2-methylcyclopropyl ketone tosylhydrazone ####**###*##*##*##*#**##« ..120 9 Vacuum pyrolysis of the sodium salt of blcyclo[4, 1.Q)-2-heptanone tosyl

hydrazone a#*#*##***##*###****#*#*###*#* . .121 10 Vacuum pyrolysis of the sodium salt of cyclopropyl methyl ketone tosylhy drazone ...... 122 11 Vacuum pyrolysis of the sodium salt of 2,2,4,4-tetraraethyIcyclobutanone tosylhydrazone and decomposition of the Intermediate dlazo compound ...... 123

INFRARED SPECTRA Figure 1 2,2-Dlmethylcyclopropyl methyl ketone...... 125 2 o(, 2 -Dlmethylcyc lopropaneme thanol...... 125 Methyl 2-methylcyc lopropyl ketone...... 125 I Dicyclopropylmethyl p-tolyl sulf one...... 125 2 -Cyc lopropyl -1,3 -bu^d lene...... 126 i 1 -Cyc lopropylcyc lobutene...... 126

Ix INFRARED SPECTRA (contd.) Figure Page 7 1-Cyclopropyl-2-cyclobutand ...... 12? 8 Cyc lopropylcyc lobut ane...... 127 9 Cyclopropanecarboxyllc acid...... 127 10 Cyclopropanecarboxyllc acid (Aldrich Chemical Company)...... 128 11 Blcyclo [1.1.0] butane...... 128 12 2-Phenyl-1,3 “butadiene...... 128 13 2-(l-Diazoethyl)-l,l-dimethylcyclo pr opane ...... 129 14 l-(l-Diazoethyl ) -2-methylcyclopropane...... 129 15 2 -D iazob icyc lo[ 4.1.0] heptane...... 129 16 Bicyclo[4.1.0] -2-heptene...... 130 17 Cyc lopropy Id iazophenylme thane...... 130 18 1-Phenylcyc lobutene ...... 130 19 1,2 -Diphenylcyc lobutene...... 131 20 Diazo ( 1-phenylcyclopropyl )methane...... 131 21 2,2,4,4 -Tetramethyldiazocyclobutane...... 131 22 2,2,4,4-TetramethyIcyclobutanone azine ...... 132 23 1-Isopropylidene-2,2-dimethyIcyclo- propane...... 132 24 Dicy c lopropylcarb inol...... 132 25 Dicyclopropylmethyl methyl ether...... 133 26 1,3-Butadiene...... 133 27 Phenylacetylene ...... 133 28 1,3,3-Trimethylcyclobutene ...... 134 29 2,4 -Dimethyl -1,3 -pentad iene...... 134 30 Trans-2-methyl-1,3-pentad iene...... 134 31 Unknown D from vacuum pyrolysis of the sodium salt of methyl 2-methylcyclopro pyl ketone tosylhydrazone ...... 135 32 l-Hepten-6-yne ...... 135 33 1 -Methylcyc lobutene...... 135 34 2-Me thy 1-1,3 “but ad iene...... 136 35 Vinylcyclopropane ...... 136

NUCLEAR MAGNETIC RESONANCE SPECTRA

36 2,2-DimethyIcyclopropyl methyl ketone...... 138 37 o^, 2 -D ime thy Icy c lopropaneme thano 1 ...... 139 38 Methyl 2rmethyIcyclopropyl ketone ...... l40 39 2-Cyc lopropy 1-1,3 “butadiene...... ,....l4l 40 1-Cyc lopropylcyc lobutene...... 142 41 1-Cyclopropyl-2-cyclobutano1 ...... 143 42. Cyc lopropylcyc lobutane...... l44 NUCLEAR MAGNETIC RESONANCE SPECTRA (contd.) Figure Page 43 1,3“Butadiene-cyclobutene mixture from vacuum pyrolysis of the sodium salt of cyclopropanecarboxaldehyde tosylhydra zone ...... 143 44 1,3-Butadiene-cyclobutene mixture from vacuum pyrolysis of the lithium salt of cyclopropanecarboxaldehyde-d tosylhydrazone...... 146 45 2-Phenyl-1,3-butadiene-phenylacetylene mixture ...... 147 46 1-Phenylcyclobutene from vacuum pyrolysis of the sodium salt of 1-phenylcyclo propanecarboxaldehyde -d tosylhydrazone .... 148 47 2-Phenyl-1,3-butadlene-phenylacetylene mixture from vacuum pyrolysis of the sodium salt of 1-phenylcyclopropane carboxaldehyde -d tosylhydrazone ...... 149 48 Mixture of 2,3-dlmethylcyclobutene and 1,3-dimethyIcyclobutene I50 49 Blcyclo[4.1.0]-2-heptene ...... I5I 50 1-Phenylcyclobutene...... 152 51 1,2-Diphenylcyclobutene...... 153 52 2,2,4,4-Tetramethylcyclobutanone azlne...... 154 53 l-Isopropylldene-2,2-dlmethylcyclopropane 155 54 1,3* 3-Trlmethylcyclobutene...... 156 55 2,4-Dime thy 1-1,3-pent ad lene...... 157 56 1 -Hept en-6 -yne...... I58 57 1-Methylcyclobutene...... 159 58 2-Methy1-1,3-butadlene ...... I60 59 Vinylcyclopropane...... I6I

ULTRAVIOLET SPECTRA 60 1-Phenylcyclobutene...... 163 61 1,2-Diphenylcyclobutene ...... l64

NEAR-INFRARED SPECTRUM 62 Blcyclo[4.1.0] -2-heptene...... I66

xl GAS CHROMATOGRAMS Figure Page 63 Product mixture from thermal decom position of cyclopropyl ketone tosylhydrazone in N-methylpyrro11- done with sodium methoxide...... I68 64 Product mixture from pyrolysis of cyclopropyIdiazophenylmethane ...... 169 65 Product mixture from vacuum pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone ...... 17O 66 Product mixture from pyrolysis of the sodium salt of cyclopropanecarbox aldehyde tosylhydrazone at atmos pheric pressure ...... 171 67 Product mixture from vacuum pyrolysis of the sodium salt of 1-phenylcyclo propanecarboxaldehyde tosylhydrazone...... 172 68 Product mixture from vacuum pyrolysis of the sodium salt of 2,2-dimethyl cyc lopropyl methyl ketone tosylhydrazone.... 173 69 Product mixture from vacuum pyrolysis of the sodium salt of methyl 2-methylcyclo propyl ketone tosylhydrazone ...... 174 70 Product mixture from vacuum pyrolysis of the sodium salt of bicycloL4.1.0]-2- heptanone tosylhydrazone ...... 175 71 Product mixture from vacuum pyrolysis of the sodium salt of cyclopropyl methyl ketone tosylhydrazone...... 176 72 Product mixture from pyrolysis of 2,2,4,4- tetramethyldiazocyclobutane ...... 177 73 Product mixture from vacuum pyrolysis of the sodium salt of cyclopropanecarbox aldehyde tosylhydrazone...... 178

xii INTRODUCTION AND HISTORICAL The principal concern of this research is the chemistry of intramolecular reactions of carbenic inter mediates generated from salts of tosylhydrazones of various cyclopropyl ketones and aldehydes (l).

(l) Intermolecular reactions of carbenic species have been reviewed by (a) J. Hine, "Divalent Carbon," Ronald Press Co., New York, New York, 1964; (b) W. Kirmse, Angew. Chem., 73, l6l (1961); (c) Ibid., n , 537, (1959); (d) Ë. Hulsgen, ibid., 6 7, 439 (1955); (e;E. Chinoporos, Chem. Rev., 6 3, S35 (19^); (f) B. Eistert in "Newer Methods of Preparative Organic Chemistry," Interscience Publishers, Inc., New York, New York, 1948, p. 513.

Carbenic intermediates may undergo three general intramolecular processes: (a) olefins or cyclic deriva tives result from insertion between carbon-hydrogen bonds; (b) addition of a carbene to a carbon-carbon double bond may occur; and (c) carbon-skeleton rearranged products result from alkyl or aryl migration (2)(3)(4).

(2) Intramolecular insertion across bonds other than carbon-carbon or carbon-hydrogen has been demonstrated in two cases by R.N. Haszeldine and R. Fields, Proc. Chem. Soc. (London), 22 (196O) and R.N. Haszeldine and J.d. Young, lïïïd.. 394 C1959), in which there is migration of a ^ -halogen atom to a carbenic center.

(3) A carbenic reaction resulting in carbon-skeleton fragmentation has been reported in which cyclopropane carboxaldehyde tosylhydrazone reacts with sodium methoxide in diethyl Carbitol at l80° to give ethylene (10^) and acetylene (lOjé): (a) L. Friedman and H. Shechter, J. Am. Chem. Soc., 82, 1002 (1960)5 (h) L. Friedman, Ph.DT dissertation, the Ohio State University, 1959* (4) A second carbenic fragmentation process was reported in yield by S.S. Cristol and J.K. Harrington, J. Org. Chem., 28, l4l3 (1963)# in which carbenic Hecomposltlon oT“nortricyclenone tosylhydrazone gives 4-ethynylcyclopentene (69^) and 4-vinylidenecyclopentene (29^).

Of the carbon-hydrogen insertion reactions, the most common is hydrogen migration to form olefins (3a,b)(3;.

(5)(a) S.M. Luck, D.G, Hill, A.T. Steward, Jr., and C.R. Hauser, J. Am. Chem. Soc., 8 1, 2784 (1959); |b) L. Friedman and 77G. Berger, ibiHT, 8 3, 500 (I9 6 1); ,c) G.B. Kistiakowsky and B.H. Mahan, iblH., 7 9, 2412 .1957); and (d) W. Kirmse, Angew. Chem., 74, T83 (1962).

Cyclohexylidene, for example, rearranges to cyclohexene in 99$^ yield (3b). If only one ^ -hydrogen is available for migration, intramolecular insertion to yield cyclo propane usually becomes significant, and if Ç -hydrogen is not present, intramolecular insertion becomes the dominant reaction (3a,b)(5b,d)(6). For example, methyl-

(6)(a) W. Kirmse and W. von E. Doering, Tetrahedron, 11, 266 (i9 6 0); (b) L. Friedman and H. Sheenter, J. Am. ^Eem. Soc., 81, 5512 (1959); (c) P.S. Skell and ATP. Krapcho, ibiHT, 8 3, 754 (1961); (d) G.L. Closs, Abstracts of 138th Meeting of the American Chemical Society, New York, New York, September, I96O, p. 9-p; (e) G.L. Closs in Chem. and Eng. News, 38, No. 3 8, 54 (196O). cyclopropane (35^) is obtained from isobutylidene, and 1,1-dimethyIcyclopropane (92^) from neopentylidene (3b). Of less frequent occurrence than hydrogen migration 3 to give olefins (1,2-insertIon) or 1,3-insertion to give cyclopropanes is carbenic insertion over longer carbon chains. 1,4-Insertion has been observed in the formation of tricycloC4.1.0.0^'^]heptane from 7-bicyclo[4.1.0]- heptylidene (7) and 4,6-dimethyl-1-mesitylbenzocyclo-

(7) W.R, Moore, H.R. Ward, and R.F, Merritt, J. Chem. Soc., 83, 2019 (196I). butene from dimesitylcarbene (8),

(8) H.E. Zimmerman and D.H, Paskovich, Abstracts of 140th Meeting of the American Chemical Society, Chicago, Illinois, September, i960, p. 2-Q; H.E. Zimmerman and D.H. Paskovich, J. Chem. Soc., 8 6, 2149 (1964).

Some 1,3-, 1,6-, and 1,7-intramolecular insertion reactions of carbenic intermediates have also been re ported (9). Although transannular reactions have not

(9)(a) D.B. Denney and D.P. Klemchuk, J. Am, Chem. Soc,, 8 0, 3289 (1 9 5); 8 (b) C.D, Guts Che anE tf.'E, Johnson, lïïld. , ^ , 5933 (1955)5 (c) C,D. Gutsche, E,P. Jason, ÏÏ75T Coffey, and H,E, Johnson, ibid., 80 5756 (1958)j (d) C.D, Gutsche, G.L, Bachman, and rTS, Coffey, Tetra hedron, 1 8, 617 (1 9 6), 2 been detected in simple 5- and 6-membered rings, they occur extensively in medium-sized rings (7 to 10 carbon atoms)(1 0) and in bicycloheptyl systems,

(1 0)(a) L. Friedman and H, Shechter, J. Am. Chem, Soc., 8 3, 3159 (1961)5 (b) R. Shantc, Ph.D. dissertation _ , , 4 the Ohio State University, 196I5 (c) A.C. Cope, G.A. Berchtold, P.E. Peterson, and S.H. Sharman, J. Am, Chem. Soc., 8 2, 6376 (i9 6 0). ----

Addition of a carbene across an iinsaturated system within the same molecule har been reported only where the unsaturated center is a carbon-carbon double bond. Carbenoid decomposition of tosylhydrazones of a number of o( , 9 -unsaturated aldehydes and ketones gives rise to cyclopropenes, a reaction which may be regarded as an internal addition of a methvlene to a carbon-carbon double bond (11). In some cases pyrazolenines are

(1 1) G.L. Closs and L.E. Closs, J. Am. Chem. Soc., 85, 3796 (1 9 6). 3 ------formed as intermediates from which cyclopropenes may be obtained by low temperature irradiation (12) probably

(1 2) G.L. Closs and W.A. BÔ11, J. Am. Chem. Soc., 8 5, 3904 (1 9 6). 3 by a non-carbenoid mechanism, but the involvement of alkenylmethylenes as reactive species has apparently been proven in some of the cases by synthesis of the same cyclopropenes from both the tosylhydrazone route, and from reaction of the alkenyllithium with methylene chloride (11)(13). Internal addition of carbenic centers

(1 3) G.L. Closs and L.E. Closs, J. Am. Chem. Soc., 85, 99 (1 9 6). 3 ------5 to double bonds can be used to form larger ring syterns as shown by decomposition of 1-dlazo-6-hepten-2-one to form blcyclo [4.1.0 ] -2-heptanone (l4).

(14) G. Stork and J. Flclnl, J. Am. Chem. Soc., 83, 4678 (1961). —

Reactions Involving carbon-skeleton rearrangement may be considered to be an Intramolecular Insertion of a carbenic center across a carbon-carbon single bond. Migration of alkyl and aryl groups Is the basis of the

Wolff rearrangement of o(-dlazoketones (15)» and the

(1 5) W.E. Bachmann and W.S. Struve, Organic Reactions, 1, 38 (1942); F. Weygand and H.J. Bestmann, Angew. CHem., 72, 535 (196O). related Süs rearrangement of o-qulnone dlazldes (1 6).

(1 6) 0. Süs, 556, 6 5, 85 (1 9 4 4).

The decomposition of o<—dlazoketones In several cases has been shown to give rearrangement products other than those expected from the normal Wolff processes. The copper-bronze-catalyzed decomposition of 1,5,5- trlmethyl-3-dlazobloyclo[ 2.2.1 ] -2-heptanone leads to formation of l,É»4-trlmethyltrlcyclo[2.2.1.0^'^ ]-3- heptanone by methyl migration (17)(18). The fact that the

(1 7) P. Yates and S. Danlshefsky, J. Am. Chem. Soc., 84, 879 (1962). ------(l8 ) It is possible that no carbene is actually involved, but rather the reactive intermediate may be an organocopper compound.

copper-catalyzed decomposition of o<-diazo-o-t-butylaceto- phenone in benzene gives only 4,4-dimethyl-l-tetralone, but in dimethyl sulfoxide gives only 2,3,3-trimethyl-l- indanone leads to the suggestion that the transition state for the carbon-carbon insertion reaction is more polar than the transition state for carbon-hydrogen insertion

(18)(19).

(1 9) P.T.Lansbury and J.G. Colson, Chem. and Ind. (London), 821 (I9 62). '

In the rearrangement of 4-diazo-2,2,5,5-tetramethyl-3- hexanone the principal product is 2,2,4,5-tetramethyl- 4-hexen-3-one; migration of a methyl group presumably occurs because of the difficulty of joining two Jb-butyl groups to the same atom, which would be required in the normal Wolff rearrangement (20). A Wolff rearrangement

(2 0) M.S. Newman and A. Arkell, J. Org. Chem., 24, 385 ( 1 9 5 9 ). ------has been carried out in one case generating an acylcarbene

intermediate by reaction of dialkyl acetylene with peracids instead of the usual o<—dlazoketones (2 1).

(21) V. Franzen, Ann., 602, 199 (1957). 7 Apart from the Wolff rearrangement. Intramolecular Insertions between carbon-carbon bonds have been reported only In a few cases. A mechanism involving rearrangement of a cyclopropylidene has been postulated for the pre paration of allene by reaction of 1,1-dihalocyclopropanes with magnesium, sodium, alkyl lithium compounds, or Grignard reagents (22)(23). Aliénés have also been

(22)(a) H, Kloosterziel, Chem. Weekblad., 39, 77 (1963); (b) W. von E. Doering and P.M. La ETainme, Tetrahedron, 2, 75 (1958); (c) T.J. Logan, Tetrahedron Letters, 173 T 196I); (d) W.R. Moore and H.R. Ward, J. Org.""Chem., 27, 4179 (1962): (e) L. Skattebdl, Tetrahedron Letters, I67 (I9 6 1). (2 3) Shank has shown that carbenes are, in many cases, formed from reaction of gem-dihalides with metals (10b). ^ formed from rearrangement of cyclopropylidene intermediates prepared from substituted cyclopropylnitrosoureas (24).

(24) W.M. Jones, M.H. Grasley, and W.S. Brey, Jr., J. Chem. Soc., 8 5, 275^ (19 6). 3

Carbon skeleton rearrangement is an important mode of reaction in the decomposition of 1-diazo-2-methyl-2- phenylpropane (2 5), and is the main reaction in the thermal

(2 5) H. Philip and J. Keating, Tetrahedron Letters, 523 ((:1961). decomposition of l-diazo^2»2-trlphenylethane and Its derivatives (2 6), Blcyclo [2.2.2 ] -1-eotanol Is the 8

(26) L. He Herman and R.L. Garner, J. Am. Chem. Soc., 57, 139 (1935); P.B. Sargeant, Ph.D. dlsserïïatîôïïT tHe~ üïïlo State University, 1962. major product from carbenic decomposition of blcyclo [2.2.1] -heptane-1-carboxaldehyde tosylhydrazone in N- methyIpyrrolidone (27 ) (2 8).

(27) J.W. Wilt and G.A. Schneider, Chem. and Ind. (London), 865 (I9 6 3). (2 8) It is not clear whether this is a carbenic process, since alcohol formation may indicate the presence of sufficient water to allow cationic processes to occur.

Except for the rearrangements of these last compounds and 4-diazo-2,2,5»5-tetramethyl-3-hexanone (2 0), carbon- skeleton rearrangements do not occur extensively in carbenoid systems of the neopentyl type (5b). There is considerable carbon-skeleton rearrangement, however, in the decomposition of diazocyclopropane, dlazocyclobutane, cyclopropyldiazomethane, and 1-cyclopropyl- diazoethane (3a)(10a). Because of the high order carbon-skeleton rearrange ment found in carbenic decomposition of tosylhydrazones of certain small ring compounds (3a)(10a), it is of Interest to expand the extent of such reactions in order to evaluate electrical and steric effects, and to examine possible synthetic utility. To this end, tosylhydrazone 9 salts were thermalyzed to dlazo compounds which subse quently decompose by carbenic mechanisms. Tosylhydrazones of aromatic aldehydes and ketones react with sodium in diethylene glycol to give aryldiazo- alkanes or their decomposition products (29). Under

(29) W.R. Bamford and T.S. Stevens, J. Chem. Soc., 4735 (1952). these conditions, tosylhydrazones of aliphatic or alicyclic ketones give olefins as principal products. Carbon- skeleton rearrangements occur in decomposition of pina- colone and camphor tosylhydrazones. In reaction of a tosylhydrazone with sodium in ethylene glycol, the base removes a proton from the tosylhydrazone to give the con jugate anion which decomposes to the toluenesulfinate ion and diazo hydrocarbons. A study of decomposition of tosyl hydrazones in protonic and aprotic solvents (3b) showed that diazo compounds in protonic solvents undergo proton transfer from solvent to diazonium intermediates which undergo cationic decomposition of the Wagner-Meerwein type involving hydrogen transfer and carbon-skeleton re arrangement along with insertion. In aprotic media, the diazo compounds undergo carbenic decomposition to yield olefins by hydrogen migration, and cyclopropanes by intra molecular insertion. In the present work, salts of tosylhydrazones of various cyclopropyl ketones and aldehydes were decomposed thermally in aprotic solvents and in the absence of 10 solvents in order to study carbenic decomposition of the intermediate cyclopropyldiazomethanes. The hydrocarbon products of decomposition of a number of these diazo compounds were examined in order to gain insight into the steric and electrical requirements for carbon- skeleton rearrangement in these small-ring systems. SUMMARY

A study has been made of the carbenic decomposition of various cyclopropyIdiazomethanes as derived from vacuum pyrolysis of lithium or sodium salts of their aldehyde or ketone tosylhydrazones. It has been found that the following intermediate diazo compounds decompose

thermally in 35-65^ yields (with respect to the lithium or sodium salt of the corresponding tosylhydrazone) to the subsequent hydrocarbons of composition indicated: (l-diazoethyl)cyclopropane : 1-methylcyclobutene (35^)* vinylcyclopropane (33^), and 2-methyl-1,3-butadiene (32^)j dicyclopropyIdiazomethane : 1-cyclopropylcyclobutene (86^) and 2-cyclopropy1-1,3-butadiene (14^); cyclopropyId iazo- phenylmethane: 1-phenylcyclobutene (100^); diazo(l-phenyl cyc lopropyl ) me thane : 1-phenylcyc lobutene (72Jë), 2- pheny1-1,3-butad iene (22^), and phenylacetylene (6^); diazopheny1(1-phenyIcyclopropyl)methane : 1,2-diphenyl cyc lobut ene; 2-d iazob icyclo[4.1.o]heptane ; bicyclo[4.1.0] •

2-heptene (84^) and l-hepten-6-yne (l6^); cyclopropyl diazome thane : 1,3-butadiene (6l^) and cyclobutene (39^);* and 2,2,4,4-tetramethyldiazocyclobutane: 1-isopropylidene-2,2-dlmethylcyclopropane (84^). Studies of the mechanisms of isomerization of cyclo

ll 12 propylmethylidenes have been conducted which Involve determination of (a) the detailed paths of carbon- skeleton rearrangement by labeling methods, and (b) the effects of cyclopropane ring substituents on the direction of ring expansion and/or collapse. The vacuum pyrolysis of the sodium salt of 1-phenylcyclopropanecarboxaldehyde-d tosylhydrazone gives principally l-phenylcyclobutene-2-d, while vacuum thermolysis of the lithium salt of cyclopropane carboxaldehyde -d tosylhydrazone yields cyclobutene-1-d (44^) and 1,3-butad iene-2-d (56^).

Decomposition of the sodium salt of 2,2-dimethyl cyc lopropyl methyl ketone tosylhydrazone gives mainly

1,3,3-trimethyIcyclobutene (77^) and 2,4-dimethy1-1,3- pentadiene (l8jé). However, vacuum pyrolysis of the sodium salt of methyl 2-methylcyclopropyl ketone tosyl hydrazone yields 1,3-d.imethylcyclobutene (39^), 2,3- dimethylcyclobutene (24^), trans-2-methyl-1,3-pentadiene

(23^), and trans-3-methyl-1,3-pentadiene (95^). DISCUSSION Thermal decompositions of sodium salts of tosylhydrazones lead to dlazo compounds which In aprotlc media decompose by carbenlc processes to give, generally, olefins by hydrogen migration and cyclopropanes or bl- cycllc derivatives by Intra-molecular Insertion (3b). High order carbon-skeleton rearrangements occur In certain small ring systems: cyclobutanone tosylhydrazone yields methylenecyclopropane by ring contraction; and cyclo propane carboxaldehyde tosylhydrazone gives cyclobutene by ring expansion and 1,3-butadiene by a collapse process (3a,b).

In order to determine If carbon-skeleton rearrange ment Is general for various cyclopropylcarbenes, the decomposition of cyclopropyl ketone tosylhydrazone In the presence of sodium methoxlde was examined In aprotlc media (Equation 1; Tos-= p-CH^CgHi^SOg-).

/ \ +NaOCH3 © > C=I3gHTbs ------^ biNNTos A T y -H00H3 Na0 -NaTbs

(1)

C =N. -Ng

1 3 14 It is found that decomposition of the tosylhydrazone in various aprotlc solvents (diethyl Carbitol, N-methylpyrrolidone, and diglyme) always leads to very poor yields (less than 15$^) of hydrocarbons, although the theoretical amount of nitrogen is usually obtained. The hydrocarbon yield is greatly lowered by various intermolecular or capture reactions which compete with the desired intramolecular processes. These side reactions result in formation of dicyclopropyImethy1 £-tolyl sulfone (Equation 2a) and dicyclopropyImethy1 methyl ether (Equation 2b); attack on the intermediate electro- philic carbene or diazo compound by strong nucleophiles such as sulfinate anion, methoxlde anion, or methanol occurs under these conditions* When quinoline is used as

CHToa (2a)

HOCH: ■CHOGH-* CH 2,H© the aprotlc solvent, nitrogen is evolved, but hydro carbon products are not formed. It is apparent that the intermediate carbene is trapped by quinoline, but the 15 structiires of the products of reaction were not investi gated. Pyrolysis of the dry sodium salt of cyclopropyl ketone tosylhydrazone in the absence of solvents leads to higher yields of hydrocarbons. Formation of the methyl ether is eliminated under these conditions since the source of methanol or methoxlde ion is removed. In pyrolysis of the dry sodium salt, an appreciable yield of sulfone is obtained. It may be that the sulfone is not obtained by attack on the intermediate carbene by external p-toluenesulfinate ion, but rather the conjugate base of the sulfone is formed directly, either by a cyclic pro cess or by an internal return mechanism in which the sulfinate ion is not expelled from the original molecule (Equation 3). Information on this point can possibly be

0 1, A A" Np' ^Tob _ ^ C H T b a ? obtained by effecting decomposition of the salt of the tosylhydrazone in the presence of labeled sodium £- toluenesulfinate. 16 In an attempt to reduce formation of the sulfone, the dry silver salt of cyclopropyl ketone tosylhydrazone was prepared, and decomposed thermally. The reaction Is uncontrollable; the salt decomposed with explosive violence, giving tars. Thermal decomposition of the silver salt suspended In diglyme Is more controllable, but gives a very low yield of hydrocarbons. Ultraviolet Irradiation of the sodium salt of cyclo propyl ketone tosylhydrazone In ether, cyclohexane, or N-methylpyrrolldone gives very low yields of hydrocarbons; thus, the photolysis method Is not practical for the study of the desired Intramolecular carbenlc processes. In order to exclude solvents and methanol, and to remove the carbene or Its rearrangement products from the decomposition site rapidly to minimize side reactions, a study was made of pyrolysis of the dry sodium salt of the tosylhydrazone under vacuum (1-2 mm.), and the decom position products were collected at -78 °, Vacuum pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone occurs safely and gives a good yield of hydrocarbons (up to 62$ after purification). The major product of thermolysis Is 1-eyelopropylcyclobutene (75-96^) (Equation 4), apparently derived from ring expansion of dlcyclopropylcarbene. The other significant hydrocarbon formed Is 2-cyclopropyl-l,3-butadlene (3-25^) (Equation 4). 17 An unidentified hydrocarbon is also formed in the pyro

lysis (0-2^).

■> +CH2=G®-4=C3H2+CH2=Glh^C (4):

(75-96JÊ)} (3-25^))

1-Cyolopropyloyolobutene is identical with the

principal hydrocarbon obtained in the previous experiments on thermal decomposition of the dry salt of cyclopropyl ketone tosylhydrazone at atmospheric pressure, or in solution, and in experiments on photolysis of the salt suspended in various aprotic solvents. The structure of 1-eyelopropylcyclobutene was de termined by spectral and chemical methods. The infrared spectrum has bands at 6,12 (C-C) and 11.76/( (cyclopro pane ring). That the product is not eyelopropyImethylene- cyclopropane as might have been formed by hydrogen migra tion is demonstrated by the lack of infrared absorption in the 5.7 -5.8 x4region typical for methylenecyclopropanes (3 0)

(30) R. Bleiholder and P. Cook in these laboratories have observed that compounds containing an exomethylenecyclopropane double-bond have a characteristic infrared absorption between 5 .7 and 5.8 x{ .

The nuclear magnetic resonaince spectrum of 1-eyelo propylcyc lobutene has absorption due to a tertiary cyclo- 18 propyl hydrogen (multiplet centering at 8 .7 0T, rel. area 1), secondary cyclopropyl hydrogens (multiplet centering at 9.51T, rel. area 4), ally 11c hydrogens (sharp singlet at 7.70T, rel. area 4), and an oleflnlc proton (broad singlet at 4.31T, rel. area 1), This nuclear magnetic resonance spectrum la that expected for 1-eyelopropyl cyc lobut ene upon comparison with that for 1-methyIcyclo butene which exhibits a closely split signal for the oleflnlc proton at 4.40Tand a sharp singlet at 7 .6 2 T for the allyllc protons (3 1).

(31) J. Shabta, and E. Gll-Av, J. Org. Chem., 20, 2893 (1963). ^ —

1-Cyclopropylcyclobutene absorbs one mole of hydrogen, employing the Brown hydrogenation technique (32), to give

(32) H.C. Brown and C.A. Brown, J. Am. Chem. Soc., 1493, 1494, 1495, 2027 (1962). ” the same product obtained by Its reduction with dllmlde. This reduction product appears, from spectral data, to be cyolopropylcyclobutane. The Infrared spectrum of eyelo propy Icyc lobutane contains bands at 8 .0 0 (cyclobutane ring) (3 3) and 12,23^ (cyclopropane ring), and no

(3 3) Infrared absorption at 8 . 1 0 ^ Is characteristic of a cyclobutane ring according to H.E. Ulery and J.R. McClenon, Tetrahedron, 19, 749 (1963). absorption In the oleflnlc region. Its nuclear magnetic 19 resonance spectrum has absorption due to a tertiary cyclo propyl hydrogen (multiplet centering at 9.24T), secondary

cyclopropyl hydrogens (multiplet centering at 9.77T), and normal aliphatic hydrogens (multiplet centering at

8.20T). HydroboratIon of 1-eyelopropylcyclobutene, followed by oxidation of the Intermediate organoboron compound with hydrogen peroxide, gives an alcohol whose spectra are consistent with a structure of 1-eyelopropy1-2-eyelo- butanol. The Infrared spectrum of the alcohol has bands at 3.02 (OH), 8.15 (cyclobutane ring), 9.08 (secondary OH), and 1 2 . 2 0 (cyclopropane ring). The nuclear magnetic resonance spectrum shows absorption for an alcoholic proton (5.77T, rel. area 1), a hydrogen adjacent to the alcoholic function (6.31T, rel. area l), a tertiary cyclopropyl hydrogen (9.18 T, rel. area l), secondary cyclopropyl hydrogens (9.75T, rel. area 4), and normal aliphatic hydrogens (8.20T, rel. area 5). Further proof of the structure of 1-eyelopropyl cyc lobutene Is Its complete conversion to 2-eyelopropy1- 1,3-butadlene at 350° (Equation 5). This Isomerization

3 ^ 0 ' CH2=0H^CHa (5»

can be carried out by Injecting a sample of 1-cyclopropyl- 20 cyclobutene into a gas chromatograph, the injection port of which was heated to 350®, then collecting the peak due to 2-eyelopropy1-1,3-butadlene for spectral and chemical identification. This diene forms a DieIs-Alder adduct with maleic anhydride which analyzes correctly for the 1:1 adducb.

The spectra of 2-eyelopropy1-1,3-butadinne confirms its structure. The infrared spectrum shows diene bands at 6.12 (C»C) and 6.26x<(CmC), and a band at 12.10 (cyclopropane ring). The nuclear magnetic resonance spectrum shows absorption for internal vinyl protons (quartet at 3 . 7 T , rel. area l), terminal vinyl protons (multiplet centering at 4 . 8 4 T , rel. area 4), a tertiary cyclopropyl hydrogen (multiplet centering at 8 .6 1T, rel. area 1), and secondary cyclopropyl hydrogens (multiplet centering at 9.46 T, rel. area 4). The minor product of the decomposition of the sodium salt of cyclopropyl ketone tosylhydrazone, 2-cyclopropyl- 1,3-butadiene, is identical with the material obtained from thermal isomerization of 1-eyelopropylcyclobutene. It has thus been found that side reactions are mini mized by vacuum pyrolysis of the sodium salt of cyclo propyl feetone tosylhydrazone, and this method offers promise for synthesis as well as a tool for investigating

theoretical aspects of carbene chemistry. The major products of intramolecular reactions of 21 dlcyclopropylcarbene are derived from carbon-skeleton rearrangement, although It Is not clear whether the diene arises directly from the intermediate carbene, or whether it is derived from thermal isomerization of 1- cyclopropylcyclobutene, or from vibrationally excited 1-cyclopropylcyclobutene or some other intermediate formed from rearrangement of the carbene (Equation 6). Oo A

i ^ GH2=GJ^|=GH2

During the present work, Frey and Stevens (34) reported

(34) H.M. Frey, private communication, 1963, and H.M. Frey and I.D.R. Stevens, Proc. Chem. Soc. (London), 144 (1964). ------that bicyclo[1.1.0]butane is the major hydrocarbon formed from thermal decomposition of cyclopropanecarboxaldehyde 22 tosylhydrazone in the presence of sodium methoxlde In diethyl Carbitol or trlglyme (triethylene glycol dimethyl ether); cyclobutene and 1,3-butadlene are minor products of the reaction (Equation 7). These workers report that the structure of bIcyclo[1.1.0]butane was proven by Its molecular weight and by comparison of the Infrared spec trum with that reported for an authentic sample.

+mocHVbE(i y\ I— ii >Cffi=NNHTbs ------f > + (7) -HOCH, X / '-- “ -NaTO^ Major Minor -ÏÏ2 Frey and Stevens note that bIcyclo[1.1.O]butane Is stable at l80°, but decomposes to 1,3-butadiene at 2500 (35)(36).

(3 5) D.M. Lemal, P. Menger, and G,¥, Clark, J. Am. Chem. Soc., 8 5, 2529 (1963), report that blcyclo[l.1.ÜJ- butane, prepared by Irradiation of allyIdlazomethane, thermally IsomerIzes completely to 1,3-butadlene within 4 minutes at 150°, but only slightly during the same Interval at 110°. At 110 a small amount of cyclobutene accompanied the diene.

(3 6) R. Srlnlvasan, J. Am. Chem. Soc., 8 5, 4045 (1 9 6), 3 reports that bIcycTo[1.1.OJbutane, prepared by Irradiation of 1,3-butadlene. IsomerIzes to 1,3-butadlene at relatively low temperature.

Because of the Implication of the observation of Prey and Stevens on the mechanism of formation of cyclobutenes and 1,3-butadienes from eyelopropyImethy1Idenes, It was of Interest to decompose the dry sodium salt of cyclopropanecarboxaldehyde tosylhydrazone using the 23 vacuum pyrolysis technique. The sodium salt of this tosylhydrazone decomposes at 125-135° under a pressure of 80 mm. to give a hydrocarbon mixture (approximately 60^ yield) consisting only of 1,3-butadiene (6 1-6256) and cyclobutene (38-39^); there Is no other hydrocarbon pro duced In significant quantity (Equation 8 ).

(61- 6256); 0 8 - 5956:):

Thermal decomposition of the sodium salt of cyclo propanecarboxaldehyde tosylhydrazone atmospheric pressure yields ethylene (0-13^), acetylene (O-IO56), and 1,3-butadlene (44-10056) along with cyclobutene (0-33^) (Equation 9). Quantitative yield of gases are produced.

P>GHt + CH2=GHQB=G% + HGSGffi + %G=GH2 (9) (0-33^) ((44-40056) (0-10^) (0-13^)

The presence of ethylene, acetylene, and 1,3-butadiene was proven by comparison of gas chromatographic retention 2k times with those of authentic samples. Cyclobutene was clearly shown to be present by the nuclear magnetic resonemce absorption of its allyllc protons at the 3 and 4 positions (sharp singlet at l A l T , rel. area 2) and the vinyl protons at the 1 and 2 positions (singlet at 4.08T, rel. area 1). Products of fragmentation, ethylene and acetylene, and of collapse of the carbenlc intermediate, 1,3- butadlene, are indeed observed in thermal decomposition of the sodium salt of cyclopropanecarboxaldehyde tosylhydra zone at atmospheric pressure. However, in neither reaction, at atmospheric pressure or at 80 mm., Is there observable blcyclo[1.1.O]butane. The fact that bicycloCl.l.O]butane is an unstable species which isomerizes to 1,3-butadiene could explain the difference in results between pyrolysis of dry salt and decomposition in a solvent, under the conditions of Frey and Stevens. The solvent could absorb the excess energy of the carbenlc intermediate or its rearrangement products, thus lowering the energy content of any bicyclo[l.l.O]butane formed sufficiently to allow it to be isolated. On the other hand, when the salt is decomposed in the absence of solvent, there fis no intermolecular path available for release of excess energy and thus any bicyclo[l.l.O]butane formed might rearrange to 1,3-butadlene. The possibility that blcyclo[l.l.O]butane is formed 25 as an Intermediate in pyrolysis of the salt, which then rearranges to the observed products must be considered. If blcyclo[l.l.O]butane Is derived from cyolopropy1- methylldene. Its formation may occur by Insertion of the carbene Into a carbon-hydrogen bond of one of the methylene positions of the cyclopropane ring. If this Insertion takes place. It Is necessary that a methylene hydrogen migrate to the carbenlc center (Equation 10), On

(10)

the other hand. If the observed products from eyelopropy1- methylldene are derived by direct routes which do not Involve a bIcyclo[1.1.O]butane Intermediate, Intra molecular Insertion Into carbon-hydrogen bonds cannot occur. A third mechanism involving Intramolecular carbon- carbon Insertion of the carbene between the 2 and 3 positions of the cyclopropane ring must be considered (Equation 11). Labeling methods cannot distinguish

between this mechanism and the direct expansion mechanism.

(11) 26 since decomposition of this b icyc loCl.l.Ol but ane, in volving initial cleavage of one of its external carbon- carbon bonds leads to cyclobutene identical to that derived by a direct route (Equation 12).

(12)

An experiment to distinguish between a mechanism involving an intermediate bicyclo[1.1.0]butane derived from carbon-carbon insertion and a mechanism involving direct expansion of the carbene could be carried out employing vacuum pyrolysis of the sodium salt of ppti- cally active 2-methylcyclopropanecarboxaldehyde tosyl hydrazone. The direct expansion route would not affect the optical activity of the system, and an optically active cyclobutene would be obtained (Equation 13a). If a bicyclo[1.1.0]butane intermediate were involved, all optical activity would be lost since the 1-me thy lb icy do -

Ll.l.O]butane is a symetrical intermediate (Equation 13b), 27

OH- b (13a Ï optically optically active active

CH* ^ b (CL3b) optically optically optically active inactive inactive

Because of the complexity of the mechanism involving Intramolecular carbon-carbon insertion, only the simpler carbon-hydrogen insertion or direct expansion routes will be compared in the following discussion. Intramolecular hydrogen insertion can be detected by labeling the hydrogen atom on the divalent carbon atom. If hydrogen migration occurs to form the bicyclo[l.l.O]- butane intermediate (Equation l4), there will be

GDÊ (14)

scrambling of the label such that in the products all the deuterium will be at the 3 position of cyclobutene (Equa tion 15a) and at the 1 position of 1,3-butadiene 28 (Equation 15b) if bloyolo[1.1.0]butane breaks down in some

■> (15a)

HDG=CH-CI£=C% (15b)

manner involving initial cleavage of one of its external carbon-carbon bonds (Equation 15); if bicyclo[l.1.0]butane breaks down in a manner involving initial cleavage of the internal carbon-earbon bond (Equation l6), 75JÈ of the deuterium must be found at the 3 position of cyclobutene (Equation l6a) and 75^ of the deuterium in 1,3-butadiene must be at the 1 position (Equation l6b)(37)(38).

(I6a) If

N/ V

HDC=CH-CH=CH2+H2G=CD-GB=CH2 (16b)) 29

(37) These percentages may be smaller because of the deuterium kinetic Isotope effect, but the difference due to this effect cannot be readily calculated without knowing more about the mode of Isomerization of blcyclo- [l.1.0]butane. (3 8) Since bIcyclo[l.1.O]butane Is probably a "puckered" molecule, the fact that the deuterium may be In the syn or anti positions would likely affect the migra- tlonal ability.

However, If the products from labeled cyclopropyl- methylldene are derived by direct routes (Equation 17) which do not Involve Intramolecular carbon-hydrogen Insertion, all the deuterium should be located at the 1 position of cyclobutene (Equation 17a) and at the 2 posi tion of 1,3-butadlene (Equation 17b).

H2G=CD-GH=CH2 (X7b)j

In order to Investigate the possibility of hydrogen scrambling, the tosylhydrazone of cyclopropanecarbox aldehyde -d was prepared from tosyIhydrazIde and cyclo propanecarboxaldehyde -d (3 9) In the aprotlc solvent, tetrahydrofuran (40). The lithium salt of cyclopropanecarbox aldehyde -d tosylhydrazone was formed by the reaction of 30

(39) Cyclopropanecarboxaldehyde-d was prepared by reduction of cyclopropyl cyanide with lithium aluminum deuteride, and shown to be completely deuterated on the carbonyl carbon by the absence of proton absorption in the aldehyde region (0-lT) of its nuclear magnetic resonance spectrum. (40) An aprotic solvent was used to minimize deuterium exchange from the labelled tosylhydrazone. n-butyllithium with the tosylhydrazone in tetrahydrofuran (40). Pyrolysis of the dry lithium salt of cyclopropane carboxaldehyde -d tosylhydrazone at 125° at 80 mm. yields only 1,3 -butad iene -2 -d (56^) and cyo lobutene -1 -d (44$^) (Equation l8) (approximately 30^ yield).

(18)

— ^ OHgsflD-OHsGHg +

Nuclear magnetic resonance spectroscopy allowed for determination of the position of deuterium in the products. The relative areas of absorptions for the aHylic protons (singlet at 7.48T) and vinyl protons (singlet at 4.0570 for cyclobutene are in a ratio of 4.1 31 to 1, indicating that there are four hydrogens at the 3 and 4 positions^ but only one proton at the 1 or 2 posi tions. All of the initial deuterium must be at the 1 or 2 positions of cyclobutene. Similarly the relative areas of absorption of the terminal vinyl hydrogens (multiplet centering at 4.907) and internal vinyl hydrogens (com plex signal between 3.4 and 4.07) for the 1,3-butadiene are in a ratio of 4.0 to 1, signifying that there are four hydrogens at the 1 and 4 positions but only one at the 2 or 3 positions. Thus the single atom of deuterium must be located at the 2 or 3 position of butadiene. It may be concluded that bicyclo[1.1.0]butane derived from intramolecular carbon-hydrogen insertion is not an intermediate in thermal decomposition of the dry salt of cyclopropanecarboxaldehyde tosylhydrazone, but rather the products may be derived from eyelopropyImethy1- idene by a direct isomerization route. Because of the discrepancy between these findings and those of Prey and Stevens, attempts were made to determine the reasons for the differences. When the sodium salt of cyclopropanecarboxaldehyde tosylhydrazone was decomposed as a slurry in dry diethyl Carbitol at 180°, the expected products of ethylene (7^), acetylene (8^), 1,3-butadiene (32$^) and cyclobutene (34^) are obtained (the yield of gases was between 62-71^). There is also a fifth hydrocarbon (l6^) of larger 32 gas chromatographic retention time, the infrared spectrum of which exhibits no double-bond absorption. This product must be the hydrocarbon to which Prey and Stevens assign the structure of bicyclo[l.1.0]butane (4l)(Equation 19).

(41) Prey and Stevens report that bicyclo[1.1.O]- butane has a longer gas chromatographic retention time, on a di(2-cyanoethpxy) ether column, than does cyclobutene. The additional hydrocarbon presently found from pyrolysis of the salt suspended in diethyl Carbitol also has a^ longer retention time than does cyclobutene on a^ - oxyd iprop ion itr ile column.

IS. © A(DEO); / \ >OH.HHTos, ----- > f — ^ N a 0 -NaTos -^2 (16^) (34^)/

(19)

HgCzzCHg + HC=CH + HgCLzCH-CHziCHg

(7^) (8^): (32^).'

Decomposition of the salt suspended in diethyl

Carbitol in the presence of a proton source or In a protonic medium gives bIcydlo[1.1.O]butane as à major product. When diethyl Carbitol with 10^ ethylene glycol is the reaction medium, there are produced 1,3-butadiene (8^), cyclobutene (28jë), and bicyclo[1.1.0]butane (64^)

(68^) yield of gases). If diethyl Carbitol containing 33 water la the decomposition medium, ethylene (10^), acetylene W ) > 1,3-but ad lene (3^), cyclobutene (50jé), and blcyclo[1.1.0]butane (33^) are formed yield of gaseous products). Decomposition of the salt In ethylene glycol yields 1,3-butadiene (6^), cyclobutene (l5Jë), and bIcyclo[1.1.O]butane (7 #^)(53^ yield of gases).

Since blcyclo[l.1.O]butane becomes an Important pro duct when the salt of cyclopropanecarboxaldehyde tosyl hydrazone decomposes In the presence of a proton donor solvent. It was of Interest to see If the tosylhydrazone Itself or £-toluenesulflnlc acid formed as a decomposition product could serve as the proton donor. When cyclopro panecarboxaldehyde tosylhydrazone was decomposed thermally In diethyl Carbitol with Insufficient (O.7 8 equivalents) sodium methoxlde, the products were ethylene (75^), acetylene (4^), 1,3-but ad lene (6^), cyclobutene {2.6%), and bIcyclo[1.1.0]butane (57^)(55^ yield of gaseous products). These results are startling when compared to the decom position of the tosylhydrazone In diethyl Carbitol In the presence of excess sodium methoxlde (1.8 equivalents). In which ethylene (9^), acetylene (8^), 1,3-butadiene (39^), cyclobutene (41^), and bIcyclo[1.1.O]butane (3^) are formed (87 ^ yield of gases). Thus, under carbenlc conditions, decomposition of the sodium salt of cyclopropanecarboxaldehyde tosylhy drazone gives very low yields of bIcyclo[1.1.0]butane 34 when carried out dry or in an aprotic solvent, or by generating the salt ^ situ from the tosylhydrazone and sodium methoxide in an aprotic solvent. When a proton source is present, however, formation of bicyclo[l.l.o]- butane becomes important; this effect may be due to solvation of the carbenic intermediate, or more likely from formation of a carbonium ion intermediate (Equation 20), the fate of which is different from that of a carbene.

[ > O H r

or ^ C H 2 ® ■>

-Nr (20)1 ©

H2<-—

In order to test the generality of the ring expansion reaction of eyelopropylraethy1idenes, it was of interest to examine 1-phenyIcyclopropylmethylidene in which phenyl migration to the carbenic center might compete with ring expansion and fragmentation. Vacuum pyrolysis of the sodium salt of 1-phenyl- 35 cyclopropanecarboxaldehyde tosylhydrazone produces a mixture of hydrocarbons (38^ after separation; Equation 2 1) the main component of which Is 1-phenyIcyclobutene (6 9-72^) derived from ring expansion. The high percentage

A -N P>KlH=Nv -NaTos

(2 1 )

Y6^5 □ + CH2=CH-C=C32+CgH^CsOm

{69-72%) (22-23^) {6-Q%))

of 1-phenyIcyclobutene formed from the Intermediate 1-phenyIcyclopropyImethy1Idene Illustrates the generality of the ring expansion reaction, and shows the utility of this reaction for synthesis. Minor components are 2- pheny1-1,3-butadlene (2 2-23^) and phenylacetylene (6-8^). 1-PhenyIcyclobutene was Identified by spectral and chemical methods. Its Infrared and ultraviolet spectra are Identical to those of an authentic sample (42).

(42) J.W.Wllt, private communication.

Its nuclear magnetic resonance spectrum has absorptions 36 for phenyl protons (2.8oT, rel. area 3), a vinyl proton (closely split signal at 3.80T, rel. area l), and two sets of non-equivalent allyllc protons (multiplet cen tering at 7 .27r, rel. area 2, and multiplet centering at 7 .357^ rel. area 2). 1-PhenyIcyclobutene rearranges to 2-phenyl-l,3- butadiene in a gas chromatograph above 120®. This 2- pheny1-1,3-butadiene forms a Diels-Alder adduct with maleic anhydride which analyses properly. The structure of the diene was confirmed by its ppectra. The infrared spectrum has bands at 6 .3 1 (phenyl), 1 0 .0 9(CHcCHg), 1 1 .0 3 (-CHg), and 12.90 (phenyl). Its nuclear magnet ic resonance spectrum shows absorptions for phenyl protons (2.74T), an internal vinyl proton (quartet centering at 3.42T), and terminal vinyl protons (complex quartet cen tering at 4.88T). The minor product of the decomposition of the sodium salt of 1-phenylcyclopropanecarboxaldehyde tosylhydrazone, 2-pheny1-1,3-butadiene, is identical with that obtained from thermal isomerization of 1-phenyIcyclobutene. It was of interest to label 1-phenyIcyclopropane- carboxaldehyde tosylhydrazone with deuterium on the car bonyl carbon atom; if 1-phenylb icyclo[1.1.o]butane derived from intramolecular carbon-hydrogen insertion is an intermediate in the pyrolysis, hydrogen migration

(Equation 22) must occur. 37

A 1 ------> (22))

. X)

Breakdown involving initial cleavage of an external bond of this 1-phenylbicyclo[1.1.0]butane will give 1- phenyIcyclobutene with all the deuterium in the 3 and 4 positions (Equation 23).

(23))

^ ° 6 % 38 Breakdown of the 1-phenylbicyclo[l.1,0]butane Involving initial cleavage of the internal bond (Equation 24) should lead to 75$^ of the deuterium in the 3 and 4 posi tions of 1-phenyloyolobutene (43)(44).

«2 « :06H5 — X > i

(24Ï

■> H,D

(43) This percentage may well vary from 75^ because of the deuterium isotope effect, but the difference due to this effect cannot be calculated without knowing more about the mode of rearrangement of 1-phenylb icyclo[1.1.0]- butane. 39 (44) Since 1-phenylbicycio[l.l.O]butane is probably not a planar molecule, the fact that both the deuterium and phenyl may be in the syn and anti positions would probably affect the course of rearrangement.

Cleavage to give the phenyl group in the 3 position can be disregarded, since 3-phenyIcyclobutene is not observed, However, if the products from labeled 1-phenyIcydo- propylmethylidene are derived by direct routes (Equation 2 5) all the deuterium should be located at the 2 position of 1-phenyleyelobutene. 1-Phenylcyclopropanecarboxalde-

C6H5 +GH2=CD-0=:CBg (2 5) D hyde-d tosylhydrazone was prepared from tosylhydrazide and 1-phenylcyclopropanecarboxaldehyde-d (45). Pyrolysis of

(4 5) 1-Phenylcyclopropanecarboxaldehyde-d was obtained by reduction of 1-phenylcyclopropyl cyanide with lithium aluminum deuteride and shown to be deuterated on the carbonyl carbon by the complete absence of nuclear magnetic resonance proton absorption in the aldehyde region (O-lT). the sodium salt of 1-phenylcyclopropanecarboxaldehyde-d tosylhydrazone at 1 mm. and 120° gives (in 53^ yield after separation) 1-phenylcyclobutene (78 ^), 2-phenyl-l,3- butadiene (l6^), and phenylacetylene (6^). Nuclear magnetic resonance spectral analysis shows (using the absorption area of phenyl hydrogens as a 40 standard of five) that the area of vinyl proton absorp tion (3 .8OT) is 0.24, whereas that of the allylic protons

(7 .2 7 and 7.53*0 la 4.0. Thjis, no deuterium was incorporated into the allylic positions of the 1-phenylcyclobutene; a mechanism consis tent with these results is formation of 1-phenylcyclo butene from 1-phenylcyclopropylmethylidene by a direct route which does not involve intramolecular carbon- hydrogen insertion. The small amount of hydrogen (24^) found at the vinyl position of 1-phenylcyclobutene can be explained assuming hydrogen exchange from the solvent in formation of the deutero-tosylhydrazone and/or its salt (both operations were carried out in methanol) (Equa tion 2 6).

0 6 % TosNHNH. CH^ONa =0 r^C=NNHTos CH^OH D(W GH3OH:

9 6 % P 6 % N s © -NaTos -N" C=NNTos [>LI © A 9 = % d :(24^h ) D(24^H)1

(26)

Ho J ^6% ? 6 % P D(24^) % \(24^); 41 Nuclear magnetic resonance analysis of the phenylacetylene formed from 1-phenylcyclopropylmethylidene shows complete loss of deuterium; no conclusions can be drawn from this observation since there may have been hydrogen exchange of the acetylenic proton in the gas chromatograph during preparative separation prior to spectral analysis. Nuclear magnetic resonance spectral analysis of the 2-pheny1-1,3-butadiene formed from pyrolysis of the salt of 1-phenylcyclopropanecarboxaldehyde-d tosylhydrazone shows only 3.3 protons in the 1 and 4 positions; thus 0.7 deuterium atoms are present at these positions. This indicates that the diene must not be formed directly from the carbenic intermediate, but probably from a 1- phenylb icyclo[l.1.0]butane, which might arise directly from an excited carbene or from "hot 1-phenylcyclobutene". The main course of rearrangement of 1-phenylcyclopropylmethylidene, however, gives 1-phenylcyclobutene which is not derived from intramolecular carbon-hydrogen in sertion. In order to obtain information with respect to the effect of cyclopropane ring substituents on the direction of ring expansion, the sodium salt of 2,2-dimethyIcyclo propyl methyl ketone tosylhydrazone was pyrolyzed at

1 mm; decomposition occurs from 175-185®. The hydrocarbon mixture contains mainly 1,3,3-trimethyIcyclobutene (7 2- 42 8 ljé) and 2,4-dlmethyl-l,3-pentadiene (11-18^), with small amounts of other unidentified hydrocarbons (Equation 27).

OHy Off. ■' © (R.T.) bNN^s A A -NaTos -Nb > CHj 3HÔ

(27)

CHj- +CH2=Ç-CS=Ç.-CH^ l > 9 ‘ bffjJ ---k

(72-81^) (11-

1,3,3-Trimethyloyolobutene was prepared in 35^ yield (after separation) by this procedure. Some 2-(l-diazoethyl)-1,1-dimethyIcyclopropane is obtained in the crude product as evidenced by its infrared band at 4.90//, but the red color of this material quickly disappears at room temperature. The structure of 1,3,3-trimethylcyclobutene is demonstrated by spectral evidence and by its conversion to 2,4-dimethyl-1,3-pentadiene at 400° (Equation 28) in a gas chromatograph. The nuclear magnetic resonance spectrum of 1,3,3-trimethyIcyclobutene shows absorption due to a vinyl proton (quartet at 4.31T, rel. area l), a closely split signal for methyl attached to a double bond (8.36T, 43 rel. area 3), two equivalent methyl groups (singlet at 8.87T* rel. area 6), and normal aliphatic protons (broad singlet at 7.93% rel. area 2). Since 1,3,3-trimethyl-

CH, CHj A (400°) ^ Q%=|;-cm=c-OH^ (28) CH CH, CH, 3- eyelobutene can be converted, thermally, to 2,4-dimethyl- 1,3-pentadiene, it is not clear whether the diene product is formed directly from the carbenic intermediate or from the eyelobutene.

It is interesting to speculate on the reasons for formation of the observed eyelobutene rather than the isomeric 2,3,3-trimethyIcyclobutene. The more electron- rich bond might be expected to migrate to the electro- phillic carbenic center, giving the isomer not actually found (Equation 29). If electrical effects are controlling

CH3

(29) CH

in this system, the transition state must be close to product, and stabilization of a developing charge in the transition state leading to product must be more important 44 than enriching the nucleophllicity of a bond by inductive effects (Equation 30).

CH- OH I CH3 CH-*=fc CHj Major © i— [j I yprocProduct H- © CH3J GH:

(3 0)

GH, cm OHy PH3 GH3 CH3^ c m © c m ©

Another explanation of the rearrangement involves steric factors. In the transition state leading to products, approach of the carbene to form 2,3,3-trimethylcyclobutene is more hindered by the methyl groups (Equation 31a) than that leading to the observed product which is hindered only by hydrogen (Equation 31b). — CH3 cm ,GH-

(3 1a);

GH3 - 3H3 GH3^ GH-* ------> (31b)

-GH3 - cm ## 45 In efforts to gain information with respect to steric vs. electronic control of ring opening, the sodium salt of trans-methyl 2-methylcyclopropyl ketone tosyl hydrazone was pyrolyzed at 5 mm.; decomposition occurs at 155-165°. The main products are trans-2-methyl-1,3- pentadiene (23-38^), trans-3-methy1-1,3-pentadiene (8- 12jé), 2,3-dimethylcyclobutene (14-230), and 1,3-dimethy1- cyclobutene (23-390) (Equation 32). The cyclobutenes were obtained in 170 yield (after separation from dienes) by this procedure. Some 1-(1-diazoethyl)-2-methylcyclopropane is obtained in the product, as shown by its infra red band at 4.9Q^, but its red color quickly disappears upon warming to room temperature.

PH: 3H: Nfi© A A(R.T. G=NNTos > =N/ -NaTos OH: -Ng GH3®

OH:, CH3 OH3 (3 2) +CH2-CH-C=0H-CH3 U GH3 CH3-J (14-230) (8-120)

OH: +GH2=C-CH=CH-0H3 rf- CH:

CH3 (23-390) (23- 46 The structures of 2,3-dlmethyloyclobutene and 1,3- dimethyley0lobutene were established from their spectrum and by the conversion of the dimethyIcyclobutene mixture to a mixture of trans-2-methyl-1,3-pentadlene (64jé) (Equation 33a)> and trema-3-methyl-1,3-pentadlene (36jé) (Equation 33b) at 400°. The structures of the dienes are

% A (400°) ^ ------^ CH2=0-CH=CHCH3 (33a)

^^5 (trans)

CH: A (400°) ■> GH2=GH-G=CHCH3 (33b) CH3 (trans) assigned by comparison with authentic samples. The nuclear magnetic resonance spectrum of the di me thylcyc lobutene mixture shows absorption of vinyl pro tons (4.35 and 4.45T)# vinyl methyl protons (one closely split singlet at 8 .38T), methyl groups (sharp singlets at 8 .8 8 and 8 .9 8T), methylene hydrogens (two multiplets cen tering at 7 .3 9 and 7.5870> and a tertiary proton (one multiplet centering at 8 .38T). From the sharp singlets of the methyl protons, the dlmethylcyclobutene mixture Is 47 shown to contain 62^ 1,3-dimethylcyclobutene and 38jé 2,3-dimethyIcycIbutene. Because of the Inability to purify the trans-methyl

2-methylcyclopropyl ketone used for the preparation of the tosylhydrazone, there is no direct evidence about the stereochemistry of the starting material. However, the

3-penten-2-ol used in the preparation of o(,2-dimethyl cyc lopropanemethanol is completely trans; the material is greater than 95^ pure by gas chromatography, and the trans configuration is assigned on the basis of the characteristic infrared band at 10.39Xf (trans -HCsCH-). Since the 3-penten-2-ol is greater than trans, the eyelopropylcarbinol produced from it by the Simmons- Smith reaction must be trans -of, 2 -dlmethylcyc lopropane - methanol, because cyclopropane formation by this reaction is a stereospecific cis addition (46), Chromic acid

(46) H.E. Simmons, E.P. Blanchard, and R.D. Smith, Cham. Soc., 8 6, 1947 (l64), and references therein. oxidation of this alcohol is expected to give mainly the more thermodynamically preferred trans-methyl 2-methyl cyc lopropyl ketone; it can be assumed, then, that the product is trans-methyl 2-methylcyclopropyl ketone tosyl hydrazone. Decomposition of the salt of this tosylhydra zone will generate a carbene which will have little ability to discriminate between the 2 or the 3 positions of the 48 cyclopropane ring if steric control is the guiding force for ring expansion; the methyl at the 2 position offers not much more steric hindrance to backside attack of the carbene (Equation 34a) than does the hydrogen at position 3 (Equation 34b).

(34a)

Hg CH cm (34b)

OH-

The results of the decomposition agree quite well with this steric explanation since attack of the carbenic center on the 3 position to give 1,3-climethylcyclobutene (62^) is only favored slightly over attack at the more electron rich 2 position to give 1,3-dlmethylcyclobutene (38^). An important experiment to definitely decide between the two effects would be to investigate the decomposition 49 of the salt of ola-methyl 2-methylcyclopropyl ketone tosylhydrazone, in which attack of the Intermediate car bene would be sterlcally hindered at the 2 position by a methyl on the aame side as the Incoming carbene. In order to determine the course of rearrangement when eyelopropyImethylldenes are part of a bIcyc11c system, the sodium salt of bIcyclo[4,1.O]-2-heptanone tosylhydrazone was pyrolyzed at 170-175° (l mm.). The product contains some 2-dlazobIcyclo[4.1.0]heptane as shown by dlazo absorption at 4.94^ In the Infrared. This red dlazo compound rapidly decomposes upon warming to room temperature. Two hydrocarbons are produced In 50^ yield (after purification): bIcyclo[4.1.0]-2-heptene (8 2-83^) from 1,2-hydrogen migration and l-hepten-6-yne (17-18^) from carbon-skeleton rearrangement (Equation 35).

A (R.T. =N -NaTOs -"2 -Nc

(35)

(17-18^) 50 The structure of b loyo lo[ 4 *. 1.0 ] -2 -heptene was proven by spectral evidence. The infrared and nuclear magnetic resonance spectra are the same as those reported

(47).

(47) W.R. Moore, H.R. Ward, and R.F. Merritt, J. Am. Chem. Soc., 83, 2019 (1 9 6) 1 record the spectra of ?Z%orcarene: nuclear magnetic resonance spectrum, two non-equivalent oleflnlc protons at 4.08T(q) and 4.60T(m); Infrared spectrum, 6.09^(0=C).

The spectra of 1-hepten-6-yne are consistent with the assigned structure. The Infrared spectrum has bands at 3 .0 5 (5C-H), 4 .7 2 (-0=0-), 5.44 (-OH=OHg), 6.08 (0=0),

6 .9 7 (-0H2-0.0-), 10.04 (-OHzOHg), and 1 0.9 0/((-OH.OHg). The nuclear magnetic resonance spectrum shows absorption for an Internal vinyl proton (signal between 4.1-4.7T), terminal vinyl protons (a multiplets centering at 4.94 and 5.I6T), and aliphatic and acetylenic protons (between 7 .6-

8.67). In the decomposition of 2-bIcyclo[4.1.0]heptylldene the major product Is not a eyelobutene, but rather the product of hydrogen migration. In this reaction the added strain In the bIcyc 11c system may be the controlling fac tor. The minor product, 1-hepten-6-yne, might be formed directly from the carbene Intermediate, or It might arise from breakdown of unstable products of carbon-skeleton rearrangement (Equation 36). The acetylene could be formed by cleavage of either bond of the cyclopropane ring, ■>

(36)

HC=C(G%)^-GH=CH

Vacuum pyrolysis of the sodium salt of eyelopropyl methyl ketone tosylhydrazone at 155-170® under 10 mm. pressure results in formation of almost equal amounts of vinyloyolopropane (28-32^), isoprene (33-40^), and 1- methylcyclobutene (31-36JÈ) in a total yield of 48^ after separation (Equation 37). Small amounts of (l-diazo-

Ne@ A(R.T. =N N -T ob —-N a T o s -Nc © CH. CH.

(37)

CH [> >Df t>CH=:CH2 + CH2=CHj)=CH2 CH. CH^^ (31-36^) (28-32^) (33-40^): 52 ethyl)eyelopropane were present in the erude produet mix ture as evideneed by a faint red eolor whieh disappears immediately upon warming to room temperature. Isoprene and 1-methyIcyelobutene are products of carbon-skeleton rearrangement, whereas vinyleylopropane is derived from 1,2-hydrogen migration. It is again not clear whether the diene is formed directly from the carbenic intermediate or from 1-methylcyclobutene. These results differ from those found by Friedman (3b) in which the major product is 1-methylcyclobutene. This difference may be due to solvation effects, as the Friedman procedure consists of heterogeneous decomposition of the salt in an aprotic solvent, whereas in the vacuum pyrolysis tech nique the carbene may rearrange either in the gas phase, or on a solid surface. Perhaps solvation of the carbenic intermediate or collision transfer with the solvent lowers its energy and allows the carbene to be more discriminating. In vacuum pyrolysis of the tosylhydrazone salt, the carbene or its related intermediates have no opportunity for lowering their energies by solvent transfer, and thus the less energetically favored processes occur competitively.

Vacuum pyrolysis of the sodium salt of eyelopropyl phenyl ketone tosylhydrazone gives a relatively stable diazo compound, eyelopropyIdiazophenyImethane, as a volâtile product (Equation 38). CyclopropyIdiazophenyImethane can be obtained in 70^ yield, and is at least 80^ pure (cal- 53 culated from the amount of nitrogen evolved upon thermo lysis), It decomposes slowly to a polymer at room

6 % bNNTOs (38)' t>£ -N^Tos temperature, but can be kept for several days at -15°; the stability is attributed to conjugation of the diazo function with the phenyl group. CyclopropyIdiazophenylmethane is thermally decom posed to a single hydrocarbon, 1-phenylcyclobutene

(Equation 39)* in yields up to 65^ (after purification). Decomposition of the diazo compound can be effected by injection into a heated port (l80°) of a gas chromato graph. Excess heating of 1-phenylcyclobutene causes isomerization to 2-pheny1-1,3-butadiene.

A 06H5 (39Ï [>E -Nï d

In the vacuum pyrolysis of the sodium salt of phenyl

1-phenylcyclopropyl ketone tosylhydrazone, diazophenyl-

(1-phenylcyclopropyl)methane is formed at 120° (l mm.) 54 (Equation 40a), but decomposes at pyrolysis temperatures to tar. 1,2-DiphenyIcyclobutene can be obtained as a product (Equation 40b), but its yield is too low to be of synthetic value. This reaction might prove useful as a method of generating diazopheny1(1-phenylcyclopropy)- methane, however.

A NNTos » (40a) -NaTos

A. =N2 (40b) —N' 7 : O6H5

The sodium salt of phenyl 1-phenylcyclopropyl ketone tosylhydrazone decomposes very slowly at lower temperatures to the corresponding diazo compound. Thermolysis of this diazo compound in the injection port of a gas chromatograph gives only diphenylacetylene; authentic 1,2-diphenylcyclo butene degrades to diphenylacetylene above 220° (Equation 4l). This type of reaction has not been previously re- 55 ported. No 2,3-dlphenyl-l,3-butadlene was detected; it might be formed from the carbene or from isomerization of 1,2-diphenyIcyclobutene, but under the conditions polymerizes.

A ^ > G 6 % G = 0 0 6 % ( 41 )

It was of interest to test the vacuum pyrolysis technique on a carbenic system which might give carbon- skeleton rearrangement resulting in ring contraction (3b). Vacuum pyrolysis of the salt of 2,2,4,4-tetramethy1- cyclobutanone tosylhydrazone gives the corresponding diazo compound (Equation 42a) which reacts slowly at -78 °, but rapidly at room temperature, to form 2,2,4,4-tetramethy1- cyclobutanone azine (Equation 42b) in high yield. The red initial product of vacuum pyrolysis of the tosylhydrazone salt is identified as 2,2,4,4-tetramethy1- diazocyclobutane by its strong infrared absorption at

4.95/^. The structure of the azine is consistent with spectral and analytical data. The infrared spectrum of this azine shows a band at 5.95//(C=N), and a doublet at 7.37// (gem-dimethy1). The nuclear magnetic resonance spec trum of the azine displays absorption for methylene protons 56 (singlet at 8 .36T, rel. area 1) and non-equivalent methyl groups (singlets at 8.6? and 8.75T, rel, area 3 each).

CH- îJNNTôs © N aTo (42a) CH

CH CH

CH CH CH

(42b)

-N

In order to obtain appreciable intramolecular reac tion, the diazo compound can be thermally decomposed in a heated injection port of a gas chromatograph which has a high helium flow rate. This technique allows the diazo compound to be sufficiently diluted with helium so that 57 azine formation is minimized. 1-Isopropylidene-2,2- d ime thyloyolopropane, the major hydrocarbon product (75- 84^), is produced in 46^ yield (after separation) from the salt (Equation 43). Three other hydrocarbons are detected, but not identified.

CHji CH3 CH GH3 .GH: (43) ^ !>=( CH: CH3 j (75-84^)

The structure of 1-isopropylidene-2,2-dimethyIcyclo propane was established by chemical and spectral methods. Ozonolysis gives acetone in 45^ yield. The hydrocarbon exhibits a band at 5.59/<(C=C) characteristic of exo- methylenecyclopropanes (30). Its nuclear magnetic resonance spectrum has absorption for two non-equivalent methyl groups (broad singlet at 8.28T, rel. area 3, and a singlet at 8.86T, rel. area 3) and secondary cyc lo propyl hydrogens (closely split singlet at 9.23T,rel. area 1). It is somewhat surprising that the major product from 2,2,4,4-tetramethyIcyclobutylidene is derived from carbon-skeleton rearrangement since the carbene could give 58 either 2,2,4,4-tetramethylhicyclo[l.l,0]butane (Equation 44a) or 1,4,4-tr imethylb icyclo[2.1.0]pentane (Equation 44b) by intramolecular carbon-hydrogen insertion.

GH, GH

(44a)'

CH3 ÜH3

CH, CHarffi

(44b) CH3 CH3 j CH^ GH3 EXPERIMENTAL

General Procedures and Techniques

Melting points Melting points below 200° were determined In an oil bath. Melting points above 200° were obtained on a Fisher melting point block. All melting points are un corrected. Bolling points Bolling points were obtained as the compounds dis tilled, unless otherwise noted. Thermometer corrections were not made. Elemental analyses Elemental analyses were performed by Galbraith Laboratories, Inc., Knoxville, Tennessee, and by Schwarzkopf Mlcroanalytlcal Laboratory, Woodside. New York, unless otherwise noted. Infrared spectra

The Infrared spectra of the compounds prepared In this research were obtained with Perkln-Elmer, Infracord, and Perkln-Elmer, Model 137 recording Infrared spectro photometers. The spectra of solid compounds were deter mined from potassium bromide wafers, and the spectra of liquid compounds from liquid films, unless otherwise noted. 59 60 Ultraviolet spectra Ultraviolet spectra were obtained with Cary, Model 14, and Perkln-Elmer, Model 202, recording spectrophoto meters . Near-Infrared spectra All near-Infrared spectra were determined using a Cary recording spectrophotometer. Model l4. Nuclear Magnetic resonance spectra All nuclear magnetic resonance spectra were obtained with a Varlan Associates nuclear magnetic resonance spectrometer. Model A-60. Spectra were determined from carbon tetrachloride solutions unless otherwise noted. Gas chromatography Gas chromatography was frequently employed as a means of product Identification, determination of pro duct composition, separation, and purification. The gas chromatographs employed were a Perkln-Elmer, Gats Practo- meter. Model 154C, equipped with a thermistor detector, connected to a 10 millivolt full-scale deflection Brown Electronlk recorder; an Aerograph, Model A-90-C, equipped with a hot-wire detector, connected to a 2,5 millivolt full-scale deflection Brown Electronlk recorder; an Aerograph, Model A-90-P, equipped with a hot-wire de tector, connected to a one millivolt full-scale deflection Bristol Dynamaster recorder; a Barber-Colman, Series 5000, equipped with a hot-wire detector, connected to a 1 mill- 6l volt full-soale deflection Sargent, Model SR, recorder. In all cases helium was used as a carrier gas. Columns used In the gas chromatographs were prepared by thoroughly coating 42-60 mesh fire brick (48) with an

(48) Purchased from the Wilkins Instrument and Research Corporation, Walnut Greek, California. ether solutldn of the substrate; then after the solvent had been removed, the coated material (49) was packed

(49) SE-30 silicone rubber substrate was purchased already applied to 42-60 mesh fire brick (20^ and 30jé). with the aid of a vibrator Into either 1/4 Inch or 3 /8 Inch outside diameter copper tubing of appropriate length. Product compositions were determined using peak areas (50). Corrections were not made for the differences

(5 0) Determination of percentage composition of hydrocarbons from peak areas Is quite accurate according to E.M, Pederlcks and F.R. Brooks, Anal. Chem., 28, 297 (1 956).

In the thermal conductivities of the compounds Involved

(5 1).

(5 1) No great error la introduced If corrections are not made for thermal conductivity differences according to M. Dlmbat, P.E. Porter, and P.H. Stross, Anal. Chem., . 2 8, 290 (1956). 62 Preparative gas chromatography Preparative gas chromatography was frequently used as a means of separation and purification of hydrocarbon products prior to chemical and physical Identification. Columns of both 1/4 Inch and 3/8 Inch outside diameter were used for separating and purifying samples ranging In size from 1 to 250 mlcrollters per Injection, de pending on the peak separation obtained. Collections of fractions were carried out manually by attaching re ceivers to the detector exit while respective peaks were being recorded on the recorder. The receivers were cooled In a Dry-Ice-Isopropanol bath. The receivers used were designed like an ordinary cold trap, but of only 1-2 ml. capacity; using these receivers, as high as 90^ of the material Injected Into the gas chromatograph could be collected, depending on properties of the particular compound.

Intermediates p-Toluenesulfonyl hydrazlde Ttosyi hydrazlde) Tosyl hydrazlde, m.p. 110-112°, was prepared as described previously (52).

(5 2) L, Friedman, R.L. Litle, and W.R. Relchle, Org. Syn., 40, 93 (i9 6 0). 63 Trlmethylsulfoxonlum Iodide Trimethylaulfoxonlum iodide was prepared by a literature method (53).

(53) R. Kuhn and H. Trlschmann, Ann., 611, 117 (1958).

1-Phenyl-1-cyanooyolopropane 1-Phenyl-l-cyanocyclopropane, b.p. 89.0-89.5°/2 mm., n|^ 1 .5 3 6 9 [lit. b.p. 98-100°/! mm., n§° I.3676 (54)]was

(5 4) E.G. Knowles and J.B. Cloke, J. Am. Ohem. Soc., 2028 (1932 ). prepared from phenylacetonltrlle, sodamlde, and ethylene bromide In liquid ammonia (55).

(5 5) The Infrared and nuclear magnetic resonance spectra verify the structure given.

Cyclopropyl ketone Cyclopropyl ketone, b.p. 80-80.5°/30 mm., was pre pared as described previously (5 6).

(5 6) O.E. Curtis, Jr., J.M. Sandrl, R.E. Crocker, and H, Hart, Org. Syn., Coll. Vol. IV, 278 (I9 6 3).

2,2,4,4-Tetramethylcyclobutanone 2,2,4,4-Tetramethylcyclobutanone, b.p. 119-128°/746 mm., n§® 1.4162, was prepared from 2,2,4,4-tetramethyl-l,3- cyclobutanedlone (57). 64

(57) W.T. Reichle, Ph.D. dissertation, the Ohio State University (1958), reports b.p. 128.5°, n§® 1.4144.

2,2-Dlmethylcyolopropyl methyl Ketone Trlmethylsulfoxonlum iodide (44 g., 0.2 mole) was added through Gooch tubing from an Erlenmeyer flask to a stirred suspension of sodium hydride (9.4 g, of a 53.6$^ dispersion In mineral oil, 0.21 mole) and dimethyl sulfoxide (l60 ml.) in a three-necked, one liter round-• bottomed flask under nitrogen over a period of 30 minutes. After the mixture had been stirred at room temperature for 45 minutes, mesltyl oxide (1 9 .6 g., 0.2 mole) in dimethyl sulfoxide (4o ml.) was added over a period of 30 minutes. The mixture was stirred at 50° for 2 hours, then at room temperature for 3 hours, then poured onto Ice and ex tracted with ether. The ether layer was separated, washed three times with water, then with saturated aqueous sodium chloride solution, and dried over aniiydrous magnesium sulfate. After the product had been concentrated, distil lation of the residue at reduced pressure gave 2,2-dlmethylcyclopropyl methyl ketone (5.5 g., 49^), b.p. 5 0- 57°/38 mm. (5 8).

(5 8) The nuclear magnetic resonance spectrum (Pig. 36) and the Infrared spectrum (Pig. 1) are consistent with the assigned structure. The Infrared spectrum has bands at 5 .9 1 (CsO) and 7.28/<(doublet for gem-dlmethyl). The nuclear magnetic resonance spectrum has absorptions due 65 to hydrogens of three non-equivalent methyl groups (singlet at 7.87.1T, rel. area 3; singlet at o.84T, rel. area 3; and singlet at 8 .9 6T> rel. area 3), a tertiary cyclopropyl hydrogen (quartet at 9.31'T', rel. area l), and secondary cyclopropyl hydrogens (multiplet between 8-9T, rel. area 2).

Anal. Calcd. for C7 H12O : C, 75.00; H, 10,71 Pounds C, 74.74; H, 11.00 Phenyl 1-phenylcyclopropyl ketone 1-Phenyl-l-cyanocyclopropane (24.2 g., 0,17 mole) was added to a stirred solution of phenyImagneslum bromide

(0 .2 mole) In benzene (90 ml.) at a rate sufficient to allow mild reflux of the reaction mixture. The addition required 15 minutes, after which the reaction mixture was held at reflux for 20 hours. Hydrolysis of the reaction product was accomplished by addition of a solution of 90 ml. concentrated hydrochloric acid In 15O ml. water. Organic solvent was removed from the mixture by distil lation. When Its boiling point reached 90^, the reaction mixture was refluxed 45 minutes. The mixture was cooled, extracted with ether, and the ether layer was washed with 5^ sodium bicarbonate, water, saturated aqueous sodium chloride, and then dried over anhydrous magnesium sulfate. After removal of ether by distillation, the crude phenyl 1-phenyIcyclopropyl ketone (3 6 .2 g., 95^) was used without further purification (5 9) for preparation of Its tosylhydrazone.

(5 9) This material is not sufficiently stable to 66 allow distillation even at reduced pressures. 1-Phenyl- cyclopropyl phenyl ketone prepared In ether solution from pheny Imagne s lum bromide and 1-phenyl-l-cyanocyclopropane by 8.0. Bunce and J.B. Clode, J. Am. Ohem. Soc., 7 6, 2244 (1954), was purified by dlstiTla^on, b.p.” T?5- T 3 7 V 1 mm. l-Phenylcyclopropanecarbo3caldehyde

1-Phenyl-l-cyanocyclopropane (26.7 g., O.I87 mole) was added In 20 minutes at 0° to a stirred suspension of lithium aluminum trlethoxyhydrlde (0 .2 8 mole) (6 0) In

(6 0) Prepared In situ from the careful addition of anhydrous ethanol (4FT5 ml,, 0.84 mole) to an ether solution of lithium aluminum hydride (1 1 .2 g. of 95^ purity, 0 ,2 8 mole), according to the method of H.G. Brown, C.J. Shoaf and O.P. Garg, Tetrahedron Letters, 9 (1959). ether (dried Immediately prior to use by distillation from lithium aluminum hydjJlde). The reaction was stirred at 0° for 2 .5 hours, then at room temperature overnight. Following hydrolysis with 3 N hydrochloric acid, the reaction mixture was extracted with ether. The ether layer was washed with water, 5$^ aqueous sodium bicarbonate, saturated aqueous sodium chloride, and then dried over anhydrous magnesium sulfate. The mixture was concentrated, and the residue was distilled under vacuum to give 5 .0 g. (18^) of 1-phenyIcyclopropanecarboxaldehyde, b.p. 64-

68°/l mm. [ lit. b.p. 6 5-71V 1 mm. (6I)].

(6 1) D.I. Schuster and J.D. Roberts, J. Org. Ohem., 51 (1962). 67 Bloyolo[4.1.0]-2-heptanone Trlmethylsulfoxonlum Iodide (22 g., 0.1 mole) was added In 30 minutes through Gooch tubing from an Erlen meyer flask to a stirred suspension of sodium hydride (4.7 g. of a 53.6^ dispersion In mineral oil, O.IO5 mole) and dimethyl sulfoxide (80 ml.) In a 500 ml. three necked round-bottomed flask under nitrogen. After the mixture had been stirred at room temperature for 30 minutes, 2-eyelohexen-1-one (9 .6 g., 0.1 mole) In di methyl sulfoxide (30 ml.) was added In 30 minutes. The reaction mixture was stirred at 55° for 2 hours, then at room temperature for 3 hours. The reaction mixture was then cooled In an Ice bath and diluted carefully with water. The mixture was extracted twice with ether, and the combined ether layers were washed 3 times with water, 2 times with saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate. Distillation of the mixture under reduced pressure gave bIcycloC4.1.0]-

2-heptanone (4.1 g., 37^), b.p. 75-85°/$ mm. (6 2). The

(6 2) W.G. Dauben and G.H. Berezin, J. Am. Chem. Soc., 8 5, 468 (1 963), report b.p. 85.0-85.5°/l(T'mm. for ‘blcyclo- pri.O]-2-heptanone prepared by oxidation of the corres ponding alcohol.

crude ketone was used without further purification for preparation of Its tosylhydrazone. 68 o(. 2 -Dlmethy Icyc lopropane - methanol Methylene iodide (115 &•, 0.43 mole) was added to a well-stirred mixture of anhydrous ether (250 ml.), zinc-copper couple (36 g., 0.55 mole) (10b), and iodine (0.2 g.). The reaction mixture was warmed until a spontaneous reaction began, as evidenced by continued refluxing of the ether when warming was discontinued. The flask containing the reaction mixture was then heated at 35°, and the mixture stirred for 30 minutes. A solution of 3-penten-2-ol (17.2 g., 0.20 mole) in anhy drous ether (40 ml.) was added to the rapidly refluxing mixture in 30 minutes. The stirred mixture was kept be tween 35-40° for 90 minutes while refluxing. The mix ture was cooled to room temperature, and a saturated aqueous ammonium chloride solution was added (60 ml.) until the inorganic salts precipitated. The ether layer was decanted, and the precipitated salts washed with additional ether. The combined ethereal solution was washed with saturated aqueous potassium carbonate solution (4 X 100 ml.), and saturated aqueous sodium chloride solution (2 x 100 ml.). The ether solution was dried over anhydrous magnesium sulfate, and the ether removed under pressure. The residual oil was added under nitrogen to a saturated methanolic solution of sodium methoxide (75 ml.), and the resulting solution was kept at room temperature for 20 hours. The methanolic solution 69 was added to ether (500 ml.),and the resulting solution was washed with saturated aqueous sodium chloride solu tion until the washings were no longer basic. The ethereal solution was dried, the ether and methanol re moved at reduced pressure, and the residue distilled to give 18.4 g. (92^) of o(,2-dlmethylcyclopropanemethanol, b.p. 75-80^/80 mm., n§^ 1.4480. Vinyl proton absorption In the nuclear magentlc resonance spectrum (Pig. 37) shows this material to contain 20^ 3-penten-2-ol; the yield of adduct was actually only 74jé. The nuclear magnetic resonance spectrum, however, of the product shows absorption due to the hydroxylIc proton (singlet at 6.4oT) and a complex series of bands between 8.7 and 9.9T . The Infrared spectrum (Pig. 2) has bands at 3.00 (OH), 9.70 (cyclopropane), and 11.54/((cyclo propane). This material was used for preparation of methyl 2-methyIcyclopropy1 ketone without further puri fication.

Methyl 2-methylcyclopropyl ketone To a stirred solution of crude o<,2-dlmethylcyclopropanemethanol (9.88 g., 0.079 mole If 80^ pure) In acetone (250 ml.) under nitrogen at 0-5° was added In 10 minutes a chromium trloxlde solution (40 ml.; prepared from 2 6 .7 g. of chromium trloxlde In 23 ml. of concen trated sulfuric acid and diluted to 100 ml. with water). Methanol (4o ml.) was then added to reduce the unused 70 ohromlum trloxlde. The solution was decanted from the chromium salts, and the salts were washed with acetone. Most of the acetone was removed by distillation through a Vlgreux column (2 x 40 cm.) under reduced pressure. The residue was dissolved In ether, the ethereal solution was washed three times with saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate. The ether was removed, and the residual oil distilled under reduced pressure to give 4.75 g. (60jé) of methyl 2-methylcyclopropyl ketone, b.p. 66-80°/f8 mm. Gas chromatography showed this material to be contaminated with up to 30^ of the starting alcohol, thus the actual yield was only 42^. The nuclear magnetic resonance spectrum (Plg. 38) of the product shows, besides small absorption due to the hydroxylIc proton of Impurity, absorption for protons of a methyl ketone (singlet at 7.87T), a normal tertiary cyclopropyl hydrogen (multiplet centering at 9.42T), and a complex series of bands between 7.9 and 9 . 0 T . The Infrared spectrum (Fig. 3) has a small amount of absorp tion In the OH region, but also shows bands at 5.91 (C=0), 9.65 (cyclopropane ring), and 1 1 .6 8 4(cyclopropane ring). This material was used for preparation of Its tosylhydra zone without further purification. 71 Cyolopropanecarboxaldehyde Cyclopropanecarboxaldehyde, b.p. 97-99^, was pre pared by reduction of cyclopropyl cyanide with lithium

aluminum hydride (6 3).

(6 3) F.T. Williams, Jr., Ph.D. dissertation, the Ohio State University, 1958, p.64.

1-Phenylcyclopropanecarboxaldehyde-d

To a stirred solution of 1-phenyl-1-cyanocyclopropane (6 .3 4 g., 0.044 mole) in ether (30 ml.) (dried immediately prior to use by distillation from lithium aluminum hydride) under nitrogen, in a 100 ml. three-necked round-bottomed flask at -15^, was added a solution of lithium aluminum deuteride (0.44 g., 0.011 mole) in dried ether (30 ml.) in 30 minutes. The reaction mixture was then stirred for 30 minutes and allowed to warm to room temperature. The reaction mixture was cooled to 0°, and 10^ aqueous sul furic acid was carefully added until the solution was acidic. The ether layer was decanted, and the aqueous layer extracted with additional ether. The combined ethereal solution was washed with 5^ aqueous sodium bi carbonate solution, saturated aqueous sodium chloride solution, and dried over anhydrous magnesium sulfate. Ether was removed by distillation at atmospheric pressure, and the residue was distilled under reduced pressure to give 4.3 g. of a mixture, b.p. 80-90°/3 mm., which was 72 shown by gas chromatography to be 53J^ 1-phenylcyclopropanecarboxaldehyde-d and 47^ 1-phenyl-1-oyanocyolopropane; this corresponds to only 35^ yield of product. This material was used without further purification for pre paration of its tosylhydrazone.

Cyclopropane carboxaldehyde-d Cyclopropanearboxaldehyde-d, b.p. 98-102®, was prepared by reduction of cyclopropyl cyanide (5.6 g., 0.084 mole) in ether (50 ml.) (dried immediately prior to use by distillation from lithium aluminum hydride) by the addition (over 30 minutes) of a solution of lithium aluminum deuteride (O.889 g., 0.0212 mole) (Metal Hydrides Co.) in dried ether (60 ml.) at -20® to -15° (64).

(64) This procedure is described by F.T. Williams, Jr., Ph.D. dissertation, the Ohio State University, 1958, p. 64.

The cyclopropanecarboxaldehyde-d was shown to contain 2Cçè cyclopropyl cyanide by gas chromatography. The aldehyde was completely deuterated at the carbonyl carbon as shown by the complete absence of proton absorption in the aldehyde region (O-lT) of its nuclear magnetic resonance

spectrum. 73 Tosylhydrazones

Cyclopropyl methyl ketone tosylhydrazone The tosylhydrazone of cyclopropyl methyl ketone, m.p. 120-122°, was prepared as described previously (3b).

Cyclopropyl ketone tosylhydrazone Cyclopropyl ketone (ll.O g,, 0.1 mole), tosylhydrazlde (l8.6 g., 0.1 mole), and methanol (50 ml.) were refluxed for 3.5 hours. The methanol was then removed under vacuum at room temperature to give a white viscous oil which crystallized at room temperature overnight. The derivative obtained was filtered, washed with cold ether (0°), and dried In vacuo. A yield of 23 g. (85$^) of cyclopropyl ketone tosylhydrazone, m.p. 110.0-111.0°, was obtained. Recrystallization of a sample from cyclohexane gave white needles, m.p. 110.5-111.5°. Anal. Calcd. for CijiHigOgNpS: C, 60.43; H, 6.4?; N, 10.07 Pound: C, 60.56; H, 6,62; N, 10.02 (6 5)

(6 5) The nitrogen analysis was carried out using a Coleman, Model 29, nitrogen analyzer.

Cyclopropyl phenyl ketone tosylhydrazone

A mixture of cyclopropyl phenyl ketone (l4.6 g., 0.1 mole), tosylhydrazlde (I8 .6 g., 0.1 mole), and methanol 74 (50 ml.) was refluxed for 6 .5 hours. The methanol was then removed under vacuum at room temperature until crystallization began. The mixture was then cooled over night at -15°. The crystalline hydrazone was filtered, washed with cold ether (O®), and dried vacuo. A yield of 29 g. (93^) of cyclopropyl phenyl ketone tosyl hydrazone, m.p. 148.0-149.0®, was obtained. Recrystal lization of a sample from cyclohexane gave white needles, m.p. 148.5-149.5°. Anal. Calcd. for CnyHisOpNoS: 0, 64.93; H, 5.73; S, 10.19; N, 8.91 Found: C, 64.34; H, 5.73; S, 10.22; N, 8.91

1-Phenylcyclopropanecarboxaldehyde tosylhydrazone 1-Phenylcyclopropanecarboxaldehyde (5 .3 g., O.036 mole), tosylhydrazlde (6.75 g., O.036 mole), and methanol (20 ml.) were refluxed for 6 hours, and then cooled at 0° overnight. The crystalline hydrazone was filtered, washed with ether, and dried in vacuo to give 10.1 g.

(90^) of 1-phenylcyclopropanecarboxaldehyde tosylhydra zone, m.p. 132-134®. Recrystallization of a sample from carbon tetrachloride gave fine white needles, m.p, 134-

136®.

Anal. Calcd. for CiyHiQOgNpS: C, 64.93; H, 5.73; S, 10.19; N, 8.91 Found: C, 65.02; H, 5.78; S, 10.35; N, 8.73 75 2,2-Dlmethylcyclopropyl methyl ketone tosylhydrazone A solution of 2,2-dimethyIcyclopropy1 methyl ketone (11.2 6., 0.1 mole) and tosylhydrazlde (18.6 g., 0.1 mole) In methanol (50 ml.) was refluxed for 5 hours. The methanol was then removed under vacuum at room temperature to give a white viscous oil which crystallized at room temperature overnight. The crystalline hydrazone obtained was collected by filtration, washed with cold ether (0°),

and dried in vacuo. A yield of 25 g. (89^) of 2,2, di me thy Icyc lopropyl methyl ketone tosylhydrazone, m.p. 121-

124°, was obtained. ReorystalllzatIon of a sample from 90^ aqueous methanol gave a white crystalline solid, m.p. 129-131°. Anal. Calcd. for Ci^HonOoNpS: 0, 60.00; H, 7.14; N, 10.00; S, 11.43 Found: 0, 60.24; H, 7.35; N, 9.85; S, 11.29

2,2,4,4-Tetramethylcyclobutanone tosylhydrazone 2,2,4,4-Tetramethylcyclobutanone (8.8 g., O .07 mole), tosylhydrazlde (13.0 g., O.O7 mole), and methanol (50 ml.) were refluxed for 8 .5 hours, and then cooled at 0° over night. The crystalline hydrazone was filtered, washed with ether, and dried jn vacuo. A yield of I8 .3 g. (88$^) of 2,2,4,4-tetramethylcyclobutanone tosylhydrazone, m.p. 148-151°, was obtained. Recrystallization of a

sample from methanol gave a white crystalline solid, m.p.

149-151°. 76 Anal. Calcd. for CicHppOpNoS: C, 61.22; H, 7.50; ^ ^ ^ N, 9.52; S, 10.88

Pound; 0, 61.23; H, 7.46; N, 9.69; S, 10.80

Bley cloL4.1.0]“2-heptanone t osyIhydrazone B l e y d o [4.1.0]-2-heptanone (3 .8 0 g., 0.0345 mole), tosylhydrazlde (6.40 g., 0.0345 mole), and methanol (25 ml.) were refluxed for 3 hours, and then cooled at 0° for 3 hours. The crystalline hydrazone was filtered, washed with ether, and dried vacuo to give 7 .5 g. (80^) of blcycloC4.1.0]-2-heptanone tosylhydrazone, m.p. 157® with decomposition. RecrystallIzatIon of a sample from methanol gave white crystals, m.p. 175® with decomposition. Anal. Calcd. for CikHnoOpNgS: C, 60.43; H, 6.47; N, 10.07; S, 11.51 Pound: C, 60.54; H, 6.57; N, 10.30; S, 11.70

Methyl 2-methylcyclopropyl ketone tosylhydrazone Methyl 2-methylcyclopropyl ketone (5.60 g., 0.040 mole If 70^ pure), tosylhydrazlde (7.44 g., 0.040 mole), and methanol (30 ml.) were refluxed for 4 hours. The methanol was then removed under vacuum at room temperature to give a colorless oil which would not solidify. This material was used directly In formation of the sodium salt of methyl 2-methylcyclopropyl ketone tosylhydrazone. 77 Cyclopropanecarboxaldehyde tosylhydrazone The tosylhydrazone of cyclopropanecarboxaldehyde, m.p. 104° with decomposition, was prepared as described previously (3b).

Cyclopropanecarboxaldehyde-d t osyIhydrazone Cyclopropanecarboxaldehyde-d (1,87 g., 0.021 mole if 8056 pure), tosylhydrazlde (3 .9 g., 0.021 mole), and tetrahydrofuran (50 ml.) were refluxed for 30 minutes. The solvent was removed under vacuum at room temperature to give a white viscous oil which crystallized at room temperature. The crystalline hydrazone was filtered, washed with dry ether, and dried jja vacuo to give 4.35 g. (87 ^) of cyclopropanecarboxaldehyde-d tosylhydrazone, m.p. 99° with decomposition. The infrared spectrum is almost identical to that of cyclopropanecarboxaldehyde tosylhydrazone.

1-Phenylcyclopropanecarbox aldehyde -d tosylhydrazone

1-Phenylcyclopropanecarboxaldehyde-d (3.85 g., 0.0138 mole if 53^ pure), tosylhydrazlde (2.56 g., 0.0138 mole), and methanol (25 ml.) were refluxed for 6 hours. The methanol was removed under vacuum at room temperature to give an oil which crystallized at room temperature overnight. The derivative was filtered, washed with dry ether, and dried in vacuo to give 3.4 g. 78 (86^) of l-phenylcyclopropanecarboxaldehyde-d tosyl hydrazone, m.p, 131-134°. The infrared spectrum is almost identical to 1-phenylcyclopropanecarboxaldehyde tosylhydrazone.

Phenyl 1-phenylcyclopropy1 ketone tosylhydrazone

Phenyl 1-phenylcyclopropyl ketone (34.0 g., 0.153 mole), tosylhydrazlde (28.4 g., O.I53 mole), and methanol (40 ml.) were refluxed for 6 hours and then cooled 24 hours at 10°. The crystalline hydrazone was filtered, washed with methanol, and dried jn vacuo to give 8.0 g. (l4^) of phenyl 1-phenylcyclopropyl ketone tosylhydrazone, m.p. l8l° with decomposition. Recrystallization of a sample from isopropanol gave light-yellow crystals, m.p. 186° with decomposition. Anal. Calcd. for Co^HppOpNoS: 0, 70.77; H, 5.64; N, 7.18; S, 8.20

Found: 0, 70.47; H, 5.65; N, 7 .26; S, 8.39

Sodium salts of tosylhydrazones: general procedure

To the tosylhydrazone in methanol was added an equimolar amount of standard sodium methoxide in methanol. As soon as the tosylhydrazone had dissolved, the colorless solution was concentrated In vacuo until a colorless oil was obtained. Anhydrous ether was added to precipitate the salt, and complete precipitation was 79 effected by cooling several hours at 0°. The fine white mlcrocrystalllne material was filtered, washed with anhydrous ether, and dried to vacuo. The salts are stable for several days at room temperature, but were generally used soon after preparation.

Lithium salt of cyclopropane- c arboxaldelxvde -d tosylhydrazone

To a solution of cyclopropanecarboxaldehyde-d tosylhydrazone (2 .2 0 g., 0.0092 mole) to tetrahydrofuran (25 ml.) was carefully added, with cooling, a 1.6 N solution of n-butyl11thlum to hexane (5.75 ml., O.OO92 mole). The cloudy reaction mixture was cooled at 10° for 3 hours to order for the salt to precipitate. Fil tration of the solid, followed by washing with ether, and drying to vacuo gave 2.21 g. (98^) of the lithium salt of cyclopropanecarboxaldehyde-d tosylhydrazone.

Preliminary Decompositions

Thermal decomposition of cyclopropyl ketone tosylhydrazone to N-metavl- pyrrolidone with sodium methoxide The tosylhydrazone was dissolved to N-methylpyrrolldone to a round-bottomed flask connected (via ground glass joints) to a Dry Ice-acetone trap which was vented to an Inverted graduated cylinder used to collect gases by water displacement. The decomposition flask was heated to l60° while the contents were stirred with a 80 Teflon-coated stirring bar propelled by a magnetic stirrer. At that temperature an equivalent amount of sodium methoxide was gradually added from an Erlenmeyer flask through Gooch tubing. Yields of nitrogen collected varied between 75^ and quantitative. After cooling the decomposition flask to room temperature, the reaction mixture was taken up in ether; the Dry Ice-acetone trap was also washed out with ether. The combined ether washings were extracted several times with water to re move N-methyIpyrrolidone, then dried over anhydrous sodium sulfate. Gas chromatographic analysis showed there to be one main hydrocarbon component (66) varying in percentage composition from 90^ to lOOJ^ of the hydrocarbon product

(66) The structure of 1-cyclopropylcyclobutene was assigned on the basis of identical gas chromatographic retention times with a sample prepared from vacuum pyro lysis of the sodium salt of cyclopropyl ketone tosylhy drazone . mixture. The percentage yield of hydrocarbons was always under 15^. Gas chromatographic analysis showed approxi mately the same amount of dicyclopropylmethy1 methyl ether (6 7) produced as hydrocarbons. Dicyc1oprppy1-

(6 7) The structure of dicyclopropyImethy1 methyl ether was assigned on the basis of identical gas chroma tographic retention times with an authentic sample, methyl p-tolyl sulfone, m.p. 115-116°, crystallized out upon concentration of the ether solution. The structure 81 of the sulfone was consistent with its infrared spectrum (Pig. 4) and chemical analysis. The infrared spectrum has bands at 6.27 (phenyl), 7.74 (doublet) (sulfone), 8.74 (sulfone), and 1 2 . 1 2 (cyclopropane). Anal. Calcd. for CniiHioSO^: 0, 67.20; H, 7.20; lo ^ 12.80

Pound; 0, 67.59; H, 7.34; 8, 12.61 Analysis of the gases produced in the decomposition showed no ethylene or other volatile hydrocarbons formed in the reaction. In a typical decomposition, 12.12 g. (0.0436 mole) of tosylhydrazone was dissolved ;Ln 50 ml. of N-methylpyrrolidone, and the resulting solution heated to l60°.

At this temperature, sodium methoxide (2.35 &•> 0.0436 mole) was gradually added. A quantitative yield of nitro gen was obtained. Gas chromatographic analysis (Pig. 63) of an ether solution of the decomposition mixture gave the following percentage composition: 52^ 1-cyclopropyIcyclo butene, 2.% unidentified unknown A, 4^ unidentified unknown B, 42$^ d icyc lopr opylme thy 1 £-tolyl sulf one.

Thermal decomposition of cyclopropyl ketone tosylhydrazone witn Sodium methoxide in other solvents Using the same procedure as described for decompo sitions in N-methyIpyrrolidone, the tosylhydrazone was 82 found to give quantitative yields of nitrogen when de composed in diglyme (diethylene glycol dimethyl ether), diethyl Carhitol (diethylene glycol diethyl ether), or quinoline. Gas chromatographic analyses of product mix tures from deccppositions in diglyme or diethyl Carhitol gave results very similar to decompositions carried out in N-methyIpyrrolidone, but the hydrocarbon yield was generally lower (less than 10^). When quinoline was used for the decomposition medium, essentially no hydrocarbon products were obtained.

Thermal decomposition of the sodium salt or cyclopropyl ketone tosylhydrazone at atmospheric pressure Using the same apparatus used for decomposition of the tosylhydrazone in N-methylpyrrolidone, the salt was added to the decomposition flask (previously heated to 160°) from an Erlenmeyer flask through Gooch tubing. Yields of nitrogen were 00^, and the yields of hydro carbon product, obtained by washing the reaction flask and trap with ether, were generally better (10-39^) than those obtained by decomposing the tosylhydrazone in N- raethylpyrrolidone. The composition of the reaction pro duct mixture was the same; one main hydrocarbon produced. Dicyclopropylmethyl p-tolyl sulfone was obtained by extracting the pot residue with ether.

In a typical decomposition, I6.I g. of the salt was 83 pyrolyzed at l60° to give an 80^ yield of nitrogen. The Dry-Ioe-acetone trap contained 2.0 g. (395^) of hydro carbon which gas chromatographic analysis showed to be better than 95^ 1-cyclopropylcyclobutene.

Thermal decomposition of the silver salt of cyclopropylketone atmospnetosylhydrazone atiz atmospnetosylhydrazone atmospheric pressure The silver salt of cyclopropyl ketone tosylhydrazone was prepared by treating a solution of the tosylhydrazone (3.66 g., 0.013 mole) and sodium methoxide (0.70 g., 0.013 mole) in methanol with a solution of silver nitrate (2.5 g.) in methanol-water. The white precipitate of silver salt was immediately filtered, wabhed with water, and dried ^ vacuo. Anal. Calcd. for Cij^H^yNgOgSAg: N, 7.27 Found; N, 7.40 (6 5) Using the same apparatus for decomposition of cyclo propyl ketone tosylhydrazone in N-methyIpyrrolidone, a 1 g, sample of the silver salt was thermolyzed. At 110° the silver salt decomposed violently, giving only tars and no volatile hydrocarbon products.

Thermal decomposition of the SilVéï’ bâlt 61 ôydloprohyi Ketone tôëyihÿWâfôhè "ih' ’difeiWg------

Using the same apparatus as that used in the decom position of the tosylhydrazone in N-methyIpyrrolidone. 84 a 1 g. sample of the silver salt suspended In 10 ml, of diglyme was decomposed by heating the mixture gradually to l60°. The yield of nitrogen was quantitative, but gas chromatographic analysis of the product showed the hydrocarbon yield to be less than 5^.

Ultraviolet Irradiation of the sodium salt of cyclopropyl ketone tosylhydrazone In several media One gram samples of the salt were suspended In 200 ml. of the solvent and Irradiated for 1 hour periods (68). The Irradiation solvents used were cyclohexane,

(68) A 450 watt Hanovla lamp enclosed In a quartz water-jacketed Immersion finger was used for the Irra diation at room temperature. ether, and N-methyIpyrrolIdone. In all cases, quantita tive amounts of nitrogen were produced along with con siderable yields of dicyclopropylmethyl methyl ether (6 9).

(6 9) If small quantities (1 ml.) of methanol were added to the reaction mixture before the Irradiation, the yields of the ether were Increased considerably.

In all cases, the hydrocarbon yield was very low and a complex mixture was obtained.

Vacuum Pyrolyses of Sodium Salts of Tosylhydrazones

General techniques The sodium salt of the tosylhydrazone (less than three grams) was placed In a round-bottomed flask (15O ml) 85 connected (via ground glass Joints) to a series of two small (5 ml. capacity) traps, cooled In Dry Ice-Iso- propanol baths, used as receivers. The pressure of the system was reduced to 1-2 mm. unless noted otherwise. The decomposition flask containing the salt of the tosylhydrazone was heated with an oil bath from room temperature to 180° at a moderate rate (15-20 mln.), and held at that temperature until all volatile products had distilled Into the traps. The system was then restored to atmospheric pressure, and the decomposition products obtained directly from the traps.

Vacuum pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone Pyrolysis of the sodium salt of cyclopropyl ketone tosylhydrazone at 1 mm. pressure gave a colorless liquid product. Decomposition of the salt occurred between 120° and l40°. Gas chromatographic analysis of the reaction mixture showed the main product to be 1-cyclo propylcyc lobutene, n§^ 1.4654, b.p. 114-115° (7 0), and a

(70) Bolling point determined by micro-boiling point technique. minor product to be 2-cyclopropy1-1,3-butadiene (Table l). During some decompositions, a third component of short gas chromatographic retention time was formed. This third component always amounted to less than 2$é and was un- 86 Identified. The structure of 2-cyclopropyl-1,3-butadiene Is consistent with the Infrared spectrum (Fig. 5), the nuclear magnetic resonance spectrum (Pig. 39), and chemical analysis of a pure sample. Anal. Calcd. for CyH^o: C, 8 9.36; H, 10.64 Pound: C, 89.24; H, 10.48 A Diels-Alder adduct, m.p. 87 -88®, was prepared with malelc anhydride. Anal. Calcd. for C, 68.75; H, 6.25 Pound: C, 68.34; H, 6.17 The structure of 1-cyclopropylcyclobutene Is con sistent with the Infrared spectrum (Pig. 6), the nuclear magnetic resonance spectrum (Pig. 40), and the chemical analysis of a pure sample. Anal. Calcd. for CyH^Q: C, 8 9.36; H, 10.64

Pound: C, 89.19; H, 10.6l The structure of 1-cyclopropylcyclobutene has been further verified by Its conversion to 2-cyclopropyl-1,3-butadiene at 350°. This conversion was accomplished by Injecting a sample Into a gas chromatograph, the Injection port of which was held above 350°. Under these conditions the gas chromatographic peak representing 1-cyclopropyl cyc lobutene completely disappeared and the sole peak obtained was that of 2-cyclopropy1-1,3-butadiene. In a typical pyrolysis, 3.426 g. of the salt wad decomposed to give, after gas chromatographic separation. 87 0.142 g. of 2-oyolopropyl-1,3-butadiene and 0.522 g of 1-cyc lopropylcyc lobutene for an overall 62Jl5 yield.

Reactions of 1-cyclopropyl cyc lobutene Hydroboration.— A solution of boron trifluoride etherate (0.25 ml.) in tetrahydrofuran (0.24 ml.) was added over a period of one hour to a stirred mixture of 1-cyclopropylcyclobutene (0.47 g., 0.005 mole), sodium borohydride (O.OO58 g., O.OOI5 mole), and tetrahydrofuran (2 .5 ml,), under nitrogen, in a 10 ml. flask. Hydrolysis was effected by adding 1 N aqueous sodium hydroxide (1 .6 ml.) and 30^ hydrogen peroxide (0.544 ml.), then stirring the mixture for one hour at 40°. The mixture was extracted with ether, and the ether layer was washed with water, saturated aqueous sodium chloride, and dried over anhydrous magnesium sulfate. Evaporation of the ether gave 0.44 g . of a pale yellow liquid. The infrared spectrum (Pig. 7) and the nuclear magnetic resonance spectrum (Pig. 4l) are consistent with a structure of 1- cyclopropyl-2-cyclobutanol. Diimide reduction.— A solution of 1-cyclopropy1- cyclobutene (0.2 g.) and tosylhydrazlde (1.0 g.) in dimethylformamide (3.0 ml.) was refluxed for one hour* After having been cooled to room temperature, the solution was taken up in ether and this ether solution extracted twice with water to remove the dimethylformamide. Gas 88 chromatographic analysis showed the absence of 1-cyclopropylcyclobutene, and the presence of only one hydro carbon component. This material was préparâtively iso lated from the ether solution using a gas chromatograph with a 3/8 in. x 5 ft. 20^ SE-30 silicone rubber column at 00®. A yield of 0.15 g. (80^) of a colorless liquid was obtained. The infrared spectrum (Fig. 8) and the nuclear magnetic resonance spectrum (Fig. 42) were con sistent with a structure of cyclopropylcyclobutane. Brown catalytic hydrogenation.— Ethanol (4.0 ml.) and 0.15 M chloroplatinic acid (0.13 ml.) were placed in a 10 ml. Erlenmeyer flask equipped with a magnetic stirrer and a side arm which was attached to a manometer (71). The platinum catalyst was generated by addition of

(71) The manometer was filled to a height such that it would allow the escape of any hydrogen above a 25 mm. differential between the flask and the atmosphere.

0.50 ml. of standard sodium borohydride solution (72).

(72) Prepared by treating 3.8 g. of sodium boro hydride in absolute ethanol with 2.0 M aqueous sodium hydroxide (5 ml.) and diluting the resulting solution to 100 ml. with absolute ethanol.

After formation of the catalyst, the mixture was stirred 2 minutes, then treated with 6 M aqueous acetic acid (0.40 ml.) to generate a hydrogen atmosphere inside the flask. To the flask was added 1-cyclopropylcyclobutene

(0.314 g., 0.0033 mole), followed by the gradual (over a 89 period of 30 minutes) addition of standard sodium boro hydride solution (0,82 ml,, equivalent to 0.0033 moles of hydrogen), at room temperature. After one equivalent of hydrogen had been taken up, the reaction mixture was extracted with ether. This ether solution was filtered to remove the platinum, washed with water, aqueous sodium bicarbonate, and aqueous saturated sodium chloride. The reduction product was préparâtIvely Isolated from the ether solution using a gas chromatograph at 80° on a 3/8 In. X 5 ft. 20^ SE-30 silicone rubber column. A yield of 0.143 g. (46^) of a colorless liquid was obtained. The Infrared and nuclear magnetic resonance spectra were Identical to those obtained from cyclopropylcyclobutane prepared by the dllmlde reduction of 1-cyclopropylcyclo butene . Permanganate oxidation.— To a mixture of 1-cyclo- propyIcyclobutene (0.179 0.002 mole) and 0.2 M aqueous potassium hydroxide (10 ml.) was gradually added (over a period of 5 minutes) at room temperature a solution of potassium permangante (O.632 g.) In water (10 ml.). Following this addition, the mixture was stirred at room temperature for 30 minutes, then acidified with 10^ sulfuric acid. The mixture was filtered, and the solid manganese dioxide was washed with ether. The fil trate was extracted with 10^ aqueous sodium hydroxide solution. This basic aqueous solution was re-acidified 90 with lOjé sulfuric acid, and then extracted with ether. The ether solution was dried over Drlerlte. The dried ether solution was evaporated to give a small amount of colorless liquid. The Infrared spectrum of a carbon tetrachloride solution of this material (Pig. 9) was Identical to the Infrared spectrum of an authentic sample of cyclopropanecarboxyllc acid (Aldrich Chemical Go.) In carbon tetrachloride solution (Fig. 10). The gas chromatographic retention times of the oxidation product were Identical to an authentic sample of cyclopropane carboxyllc acid.

Vacuum pyrolysis of the s o d l ^ salt of cyclopropanecarboxaldihyde tosylhydrazone The sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone was pyrolyzed at 80 mm. pressure to give a color less volatile liquid product which boiled below room temperature. The decomposition temperature of the salt ranged between 120-135°. Gas chromatographic analysis showed the presence of essentially only 1,3-butadlene and eyelobutene (Table 2). Only trace amounts of hydro carbons with longer retention times were observed.

The nuclear magnetic resonance spectrum (Fig. #3) of the product mixture clearly shows the presence of 1,3- butadlene and eyelobutene, since there Is absorption due to ally11c protons at the 3 and 4 positions of eyelo butene (sharp singlet at 7»^7T)# vinyl protons at the 91 1 and 2 positions of oyclobutene (singlet at 4.08T), terminal vinyl protons at the 1 and 4 positions of 1,3- butadiene (multiplet centering at 4.90T), and Internal vinyl protons at the 2 and 3 positions of 1,3-butadiene (complex signal between 3.5 and 4 . 0 T ] .

Pyrolysis of the sodium salt of oyclopropanecarboxaldehyde tosylhydrazone at atmospheric pressure In order that all volatile products would be trapped, the salt was decomposed at atmospheric pressure, employing an apparatus which was vented to an inverted graduated cyclinder used to collect gases by water displacement. In all cases the theoretical yield of gases were obtained. Gas chromatographic analysis showed the presence of ethylene, acetylene, 1,3-butadiene, and eyelobutene as the principal products (Table 3).

Thermal decomposition of cyclo propane carboxaIdehyde tosylhy drazone in diethyl Carbitol Oyclopropanecarboxaldehyde tosylhydrazone in diethyl Carbitol (20 ml.) was placed in a 50 ml. round-bottomed flask connected to an inverted graduated cylinder used to collect gases by water displacement; provision was made for sampling the gases above the decomposition flask as well as in the inverted cyclinder. The decomposition flask was heated from room temperature to 180° while the contents were stirred with a Teflon-coated stirring bar 92 propelled by a magnetic stirrer. The volume of gases collected in the inverted cylinder was not measurably different from gas displaced by expansion. Sampling of the vapor above the decomposition flask showed (Table 4) the presence of acetylene (21^), trace amounts of cyclobutane and/or 1,3-butadiene, and a high percentage (69^) of a material to which is assigned the structure of bicyclo 1.1.0 butane on the basis of the absence of double-bond absorption in the infrared spectrum (Fig. 11), and on the basis of the gas chromatogisaphic retention time which is longer than eye lobutene on either a (3,^ -oxydipropionitrile or a -iminodipropionitrile column (73).

(7 3) H.M. Prey and I.D.R. Stevens, Proc. Chera. Soc. (London), l44 91964), report that thermal decomposition of oyclopropanecarboxaldehyde tosylhydrazone with sodium methoxide in diethyl Carbitol or diglyme, principally yields bicycloLl.l.O]butane. This compound has a gas chromatographic retention time longer than does eyelo butene on a di-(2-cyanoethoxy) ether column, and was identified from its molecular weight and infrared pro perties.

Thermal decomposition of cyclopro pane carboxaldehyde tosylhydrazone in diethyl Carbitol with insufficient sodium methoxide Cyclopropanecarboxaldehyde tosylhydrazone (I.131 g., 0.00475 mole) and sodium methoxide (freshly opened bottle of better than 95^ purity) (0.20 g., 0.0037 mole) in diethyl Carbitol (20 ml.) were heated to 180° using the apparatus described for decomposition of cyclopropane- 93 carboxaldehyde tosylhydrazone In the absence of base. The yield of gases (0.0041 mêle) after correcting for expansion was 55Jé of theoretical (assuming 1 mole of nitrogen and 1 mole of hydrocarbon from 1 mole of tosyl hydrazone salt), based on the amount of sodium methoxide used. Gas chromatographic analysis of the gaseous pro ducts (Table 4) showed the main product to be bicyclo- [l.l.O]butane (57^)» with lesser amounts of ethylene (7^), acetylene (4^), 1,3-butadiene (6jé), and eye lobutene (26$).

Thermal decomposition of cyclopropanecarboxaldehyde tosylhydrazone in diethyl Carbitol with excess sodium methoxide Oyclopropanecarboxaldehyde tosylhydrazone (1.00 g., 0.0042 mole) and sodium methoxide (0.40 g., 0.0075 mole) in diethyl Carbitol (20 ml.) were heated to l80° using the apparatus described in the previous experimehts. The yield of gases (0.0073 mole) was 87 $ of theoretical based on the amount of tosylhydrazone used. Gas chromatographic analysis of the gaseous products (Table 4) showed the major hydrocarbons to be eyelobutene (41$) and 1,3- butadiene (39$); minor components were acetylene (8$), ethylene (9$), and bicyclo[1.1.0]butane (3$). 94 Thermal decomposition of the sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone In diethyl Carbitol The sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone In diethyl Carbitol (20 ml.) was thermalyzed by heating from room temperature to l80° In an apparatus described In the previous experiments. The yields of gases ranged between 62-71^. Gas chromatographic analysis (Table 5) showed 1,3-butadlene (32-35^) and eyelobutene (34-4ljë) to be the major products, with lesser amounts of ethylene (7/^), acetylene (8-l4^), and blcyclo[l.l.O]- butane (10-l6jé).

Thermal decomposition of the sodium salt of oyclopropanecarboxaldehyde tosylhydrazone In diethyl Carbitol with lOjé ethylene glycol The sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone In diethyl Carbitol (l8 ml.) and ethylene glycol (2 ml.) was thermalyzed by heating from room temperature to l80° In an apparatus described In the previous experl- mêfats. The yield of gases amounted to 68^. Gas chroma tographic analysis (Table 5) showed the major product to be blcyclo[l.l.O]butane (64^), with the minor products being eyelobutene (28^) and 1,3-butadiene (8^). Only traces of acetylene or ethylene were produced In the de composition. 95 Thermal decomposition of the sodium salt of oyclopropanecarboxaldehyde tosylhydrazone In diethyl Carbitol with 1.255^ water.

The sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone In diethyl Carbitol (20 ml.) and water (0.25 ml.) was thermalyzed by heating from room temperature to 180° as described In the proceeding experiment. The yield of gases produced amounted to 72jé. Gas chromatographic analysis of the gaseous product (Table 5) showed the major components to be bIcyclo[1.1.0]butane (33^) and eyelobutene (50$), with lesser amounts of acetylene (4$), ethylene (10$), and 1,3-butadiene (3$).

Thermal decomposition of the sodium salt of oyclopropanecarboxaldehyde tosylhydrazone In ethylene glycol

The sodium salt of oyclopropanecarboxaldehyde tosyl hydrazone In ethylene glycol (20 ml.) was decomposed by heating to l80° from room temperature as described In the previous experiments. The yield of gases was 53$. Gas chromatographic analysis of the gaseous product (Table 5) showed the main component to be b1eyelo[1.1.0]butane (74$), with minor amounts of 1,3-butadiene (6$) and eyelobutene (15$). Only trace quantities of ethylene and acetylene were formed. 96 Vaouiam pyrolysis of the lithium salt of oyolopropanecarljoxalde^ Hyde-a tosylhydrazone The lithium salt of cyclopropanecarboxaldehyde-d tosylhydrazone was pyrolyzed at 80 mm. to give a colorless liquid product; the decomposition took place gradually starting at 125°. Gas chromatographic analysis showed the presence of 2$ acetylene, 550 1,3-butadiene, 430 eyelobutene, and less than 10 of hydrocarbons of longer retention time. Nuclear magnetic resonance analysis of the crude reaction mixture (Fig. 44 ) showed the only hydrocarbon products to be 1,3-butadiene (560) and cyclobutene (440); there was also considerable tetrahydrofuran present. The nuclear magnetic resonance spectrum of the mixture showed the ratio of methylene protons to vinyl protons In cyclobutene to be 4.1, and the ratio of ter minal vinyl protons to Internal vinyl protons In 1,3- butadlene to be 4.0.

sodium yde tosylhyd] The sodium salt of 1-phenylcyclopropanecarboxaldehyde tosylhydrazone was pyrolyzed at 1 mm. pressure to give a colorless liquid product. The decomposition temperature of the salt ranged between 110° and 115°. Gas chroma tographic analysis showed the main product to be 1-phenylcyclobutene; 2-phenyl-1,3-butadiene and phenylacetylene were present as minor components (Table 6). 97 The structure of 2-phenyl-1,3-butadiene is consis tent with the infrared spectrum of pure material (Pig. 12), and with the nucleeur magnetic resonance spectrum which was taken of a mixture of the material and approximately 25Jé phepÿlacetylene (Pig. 45). A Diels-Alder adduct of the diene was prepared with maleic anhydride, m.p. 101,5- 102.0°. Anal. Calcd. for C^j^H^gOg: C, 73.68; H, 5.26

Pound: C, 73.77; H, 5.25 In a typical pyrolysis, 1.214 g. of the salt was decomposed to give 0.364 g. (78 ^) of crude product mix ture. Gas chromatographic separation of this mixture yielded 0.135 g. of 1-phenyIcyclobutene and 0.042 g. of a mixture of 2-phenyl-1,3-butadiene and phenylacetylene for an overall 38jé yield.

Vacuum pvrolj^sis of thet: sodium salt of i-phenylcyclol-phenyicvclo ropane- carboxaldehyde^ tosv razone The sodium salt of 1-phenyIcyclopropanecarboxalde- hyde-d tosylhydrazone was pyrolyzed at 1 mm. pressure to give a colorless liquid product; the decomposition took place at 120°. Gas chromatographic analysis showed the product to be 78 ^ 1-phenyIcyclobutene, 16^ 2-phenyl-1,3- butadiene, and 6$ phenylacetylene.

In the pyrolysis, 1.35 g. of the salt was decomposed, then subjected to preparative gas chromatography to give

0 .2 1 5g. of 1-phenyIcyclobutene and 0 ,0 5 7 g. of a mixture 98 of 2“phenyl-1,3-butadiene and phenylacetylene, for a total yield of 53^. Nuclear magnetic resonance spectral analysis (Fig, 46) of the 1-phenyIcyclobutene fraction showed there to be 24^ of a proton at the vinyl position, whereas there were 4.0 protons at the allylie position; thus no deuterium was present at the 3 or 4 positions of 1- phenyIcyclobutene, but 24jé of the deuterium was lost from the 2 position.

Nuclear magnetic resonance spectral analysis (Fig. 4 7 ) of the 2-phenyl-1,3-butadiene and phenyl acetylene mixture shows complete absence of deuterium in the phenylacetylene while the 1 and 4 positions of 2- pheny1-1,3-butadiene contains 3.3 protons.

Vacuum pyrolysis of the sodium salt of 2,2-dimethyIcyclopropyl 1 ketone tosylhydrazonemethyl tosy

The sodium salt of 2,2-dimethylcyclopropyl methyl ketone tosylhydrazone was pyrolyzed under 1 mm. pressure to give a pink liquid product which turned colorless very rapidly upon warming to room temperature. The pink color was due to small amounts of diazo compound as was shown by its weak infrared absorption at 4 . 9 0 ^ (Fig. 1 3). The decomposition point of the salt ranged from 175° to 185°. Gas chromatographic analysis of the products showed the presence of 1,3,3-trimethyIcyclobutene, 2,4- 99 dimethy1-1,3“pentadiene, and small amounts of unidentified hydrocarbon products (Table 7). In a typical decomposition, 2.32 g. of the salt was pyrolyzed and the liquid product was separated by preparative gas chromatography to give 0.26 g. of 1,3,3- trimethylcyclobutene (35^ yield). The structure of the main product of the decomposi tion was shown to be 1,3,3-trimethylcyclobutene by spec tral evidence and by its conversion to 2,^-dimethy1-1,3- pentadiene at 400°. This isomerization was carried out by injecting a sample of the crude reaction mixture into a gas chromatograph, the injection port of which was kept at 400°. Under these conditions the peak repre senting the main product of salt pyrolysis disappeared, and the 2,4-dimethy1-1,3-pentadiene peak was greatly increased. This 2,4-dimethyl-1,3-pentadiene was collected for spectral identification.

Vacuum pyrolysis of the sodium salt of methyl 2-methyIcyclopropyl ketone tosylhydrazone The sodium salt of methyl 2-methylcyclopropyl ketone tosylhydrazone was pyrolyzed at 5 mm. pressure to give a pale pink liquid product which turned colorless very rapidly upon warming to room temperature (74). The

(74) A small amount of white crystalline material, possibly the azine, was observed on the walls of the trap and cooler parts of the pyrolysis vessel. Sinne this 100 material was formed in very small quantities, it was not collected for positive identification. pink color was due to small amounts of diazo compound as was shown by the infrared absorption at 4.90/< (Fig. 14).

The decomposition point of the salt ranged between 155- 165°. Gas chromatographic analysis of the product mix ture showed the presence of five principal components (Table 8). Pour of the main components have been identi fied as trans-2-methyl-1,3-pentadiene, trans-3-methyl- 1,3-pentadiene, 2,3-dimethyIcyclobutene, and 1,3-dimethyl cyc lobutene.

In a typical decomposition, I.7 8 g. of the salt was pyrolyzed, and the liquid product was separated by pre parative gas chromatography to give O.O88 g. of a mixture of 2,3-dimethyIcyclobutene and 1,3-dimethylcyclobutene (17^). This mixture could not be separated préparâtively5 gas chromatographic analysis of the mixture using a 100 ft, squaIene capillary column showed the existence of the two dimethylcyclobutenes, but would not allow quantitative determination of the mixture composition. Attempted gas chromatographic analysis of the dimethyIcyclobutene mix ture using a variety of polar and non-polar packed columns did not allow even qualitative composition determination.

The structure of 2,3-dimethylcyclobutene and 1,3- dimethylcyclobutene were established by conversion of the mixture into trans-2-methyl-1,3-pentadiene and trans-3- methy1-1,3-pentadiene at 400°. This isomerization was 101 carried out by injecting a sample of the mixture of eyelobutene8 Into a gas chromatograph, the Injection port of which was kept at 400°. Under these conditions, the peak representing the combined cyclobutenes disappeared, and peaks with retention times Identical to authentic trans -2 -methyl-1,3 -pentadIene (64-695^) and trans-3- methyl-1,3-pentadlene (31-36^) were obtained. The nuclear magnetic resonance spectrum of the fraction corresponding to the mixture of cyclobutenes (Pig. 48) was that anticipated for 2,3-dimethyIcyclo butene and 1,3-dImethylcyclobutene. There Is absorption due to vinyl protons (4.35 and 4.45T), vinyl methyl protons (one closely split singlet at 8 ,3 8T), methyl groups (sharp singlets at 8 .8 8 and 8 .9 8T), methylene hy drogens (two multiplets centering at 7.39 and 7*58T), and a tertiary proton (one multiplet centering at 8 .3 8T), Using the sharp singlets due to the methyl protons, the cyclobutene mixture was found to contain 62^ 1,3-dImethyl cyc lobutene and 38^ 2,3-dimethyIcyclobutene.

Vacuum pyrolysis of the sodium salt of •feicycl5T4'.T.6J-g^----- heptanone tosylhydrazone The sodium salt of bicyclo[4.1.0]-2-heptanone tosyl hydrazone was pyrolyzed under 1 mm. pressure to give a pink liquid product which turned colorless upon warming to room temperature. The pink color was due to small amounts of diazo compound as shown by an absorption band 102 at 4 .9 4^ In the Infrared spectrum (Pig. 15). The decomposition temperature varied between 170° and 175°. Gas chromatographic analysis of the reaction product mixture showed only two products (Table 9). The main component was bicyclo[4.1.0]-2-heptene and the minor component was 1-hepten-6-yne.

The structure of bicyclo[4.1.0]-2-heptene was consistent with the infrared spectrum (Pig. 1 6), the nuclear magnetic resonance spectrum (Pig. 49), the near- infrared spectrum (Pig. 62)(75)> and the chemical analysis

(7 5) A near-infrared band\n 1.639/^(e 0.315) is very characteristic of a 1,2-disubstituted cyclopropane. A correlation of extinction coefficients for the 1.6 35- 1.640xfband of eyelopropyl methylene groups by Dr. P. Gassman has shown that there is an e value of approximately 0 .3 for each unsubstituted cyclopropane methylene group. (Personal communication) of a pure sample.

Anal. Calcd. for CyHio: 0, 8 9.3 6; H, 10.64 Pound; C, 89.04; H, 10.8l The nuclear magnetic resonance spectrum of bicyclo- [4.1.0]-2-heptene has absorption for non-equivalent ole- finic protons (multiplet centering at 4.06 T and a multi plet centering at 4 .6 9 T, rel. area 1 for each), tertiary eyelopropyl hydrogens (multiplet centering at 8.83 7', rel. area 2), secondary eyelopropyl hydrogens (multiplet centering at 9.32T, rel. area 2), and normal aliphatic protons (multiplet centering at 8.37", rel. area 4). The 103 infrared spectrum of blcyclo[4.1.0]-2-heptene has bands at 6.10 (C=C), 12.02 (cyclopropane ring), and 13.48xY (cis-olefin). In a typical decomposition, 1.316 g. of the salt was pyrolyzed, and the liquid product subjected to pre parative gas chromatographic separation to give 0 .0 3 5 6g. of 1-hepten-6-yne and O.179I g. of bicyclo[4.1.0]-2- heptene corresponding to a 30^ total yield.

Vacuum pyfolysis of the sodium salt of eyelopropyl methyl ketone tosylhydrazone The sodium salt of eyelopropyl methyl ketone tosyl hydrazone was pyrolyzed under 10 ram. pressure to give a pink liquid product which turned colorless immediately upon warming to room temperature, probably indicating the presence Initially of a small amount of diazo compound. The decomposition point of the salt ranged between 155*^ and 170°. Gas chromatographic analysis of the products showed the presence of 1-methyIcyclobutene, 2-methyl- 1,3-butadiene, and vinyloyclopropane in almost equal amounts (Table 10).

In a typical decomposition, 2.031 g. of the salt was pyrolyzed, and the liquid product subjected to preparative gas chromatographic separation to give 0 .0 6 2 1g. of 1- methyIcyclobutene, 0 .1 0 2 9g. of 2-methyl-1,3-butadiene and 0 .0 7 4 5 g. of vinyloyclopropane for an overall yield of 48^. 104 Vacuum pyrolysis of the sodium salt of oyclopropyl pheiOT ketone tosylhydrazone The sodium salt of oyolopropyl phenyl ketone tosyl hydrazone was pyrolyzed at 1 mm. pressure by heating the decomposition vessel to l40°. A red material began to form at 100° which distilled Into the trap. The red liquid product was shown to be a diazo compound by a strong Infrared absorption at 4.90^ (Pig. 17). This eyelopropyldlazophenylmethane decomposed slowly to a polymer at room temperature, but could be kept for several days at -15°.

Pyrolysis of cyclopropyldiazophenylmethane Decomposition of the diazo compound was accomplished by Injecting a sample Into a gas chromatograph, the In jection port of which was kept 6t l80°. If the length of the gas chromatographic column was reduced to one foot and the column temperature kept below 120°, the sole hydrocarbon product was 1-phenyIcyclobutene (Plg. 64). At higher column temperatures or with longer columns, a rearrangement product was also observed, which was 2- pheny1-1,3-butadIene. The structure of the sole pyrolysis product was shown to be 1-phenyIcyclobutene by comparison of Its

Infrared spectrum (Pig. 18) and ultraviolet spectrum (Pig. 60) to a sample of 1-phepyIcyclobutene prepared by an alternate synthesis (76). The nuclear magnetic reson- 105

(76) J.W. Wilt, private co m m u n i c a t i o n , 255 (6 13,850). ance spectrum (Fig. 50) is consistent with the assigned structure. In a typical decomposition, 3.00 g. of the salt of eyelopropyl phenyl ketone tosylhydrazone was pyrolyzed to give 1.03 g. (70^) of the cyclopropyldiazophenylmethane, This diazo compound was decomposed in a gas chromatograph to give 0 .6 5 g. of 1-phenylcyclobutene (65^ yield from the salt).

t o s y l h y

The sodium salt of phenyl 1-phenyIcyclopropyl ketone tosylhydrazone was pyrolyzed at 1 mm. pressure by heating the decomposition vessel to l60°. A red material began to form at 120°; this would not distill over into the trap, but turned black rapidly. Solid-liquid chromatography yielded a small amount of a light green crystalline material which was shown to be 1,2-diphenyIcyclobutene, m.p. 5 0-53°. The nuclear magnetic resonance spectrum (Pig. 51), infra red spectrum (Fig. 19), and ultraviolet spectrum (Fig. 6 1) of the product were in perfect agreement with a sample of 1,2-diphenyIcyclobutene, prepared by G. Kaugers in these laboratories by an alternate route. 106 Pyrolysis of diazophenyl- (1-phenylcyclopropyl) methane The sodium salt of phenyl 1-phenylcyclopropyl ketone tosylhydrazone slowly decomposed at room tempera ture to the corresponding diazo compound. A sample of salt which had been allowed to stemd at room temperature for 60 days was extracted with anhydrous ether and fil tered to give a red solution of diazo compound. After the ether had been removed, a red oil remained, the infrared spectrum (Pig. 20) of which showed the presence of a diazo band at 4.90Xf, but also a band at 5.96//, probably Indicating oleflnlc decomposition products. Decomposition of the diazo compound was carried out by Injecting a sample into a gas chromatograph, the Injection port of which was held above 220°. The only product obtained was diphenylacetyIene In 35^ yield (77). It was shown that a

(77) The formation of diphenylacetyIene was proven by comparison of gas chromatographic retention ;gime with an authentic sample of diphenylacetyIene at 220 on a 1/4 In. X 7 ft. 30^ SE-30 silicone rubber column.

sample of 1,2-diphenyIcyclobutene Injected Into the gas chromatograph under the same conditions decomposed to dipheny lacety Iene. 107 Vacuum pyrolysis of the sodium salt of 2,6,4,4-., , -T, ^ -te tramethyl - cyolohutanone tosylhydrazone The sodium salt of 2,2,4,4-tetramethylcyclobutanone tosylhydrazone was pyrolyzed at 1 mm. pressure by heating the decomposition vessel up to 200°. A red liquid began to form In the trap at 140° along with some 2,2,4,4-tetra- methylcyolobutanone azlne. The red liquid product was shown to be a diazo compound by a strong Infrared absorp tion at 4.95//(Pig. 21). This diazo compound rapidly decomposed at room temperature; no trace of diazo compound remained after five minutes at room temperature. Spontan eous decomposition of the diazo compound In the condensed phase led to a 66^ yield of 2,2,4,4-tetramethylcyclobutanone azlne, m.p. 98-100°. The structure of the azlne was consistent with Its nuclear magnetic resonance spec trum (Fig. 52), Infrared spectrum (Plg. 22), and chemical analysis.

Anal. Calcd. for Ct^Hoq No : C, 77.42; H, 11.30; J.D ^ 11.30

Pound; C, 77-60; H, 10.93; N, 11.51

High dilution vapor phase decom position of 2,2,4,4-tetramethyl- dlazocyclobutane Azlne formation was minimized by decomposing the diazo compound In the vapor state under high dilution with helium. The crude diazo compound was removed from the Dry Ice-Isopropanol trap by syringe, and Immediately Injected 108 Into a gas chromatograph with a high helium flow rate, the injection port temperature of which was kept at l60°. Using this technique, four hydrocarbons were produced; the main product was 1-is opropy1idene-2,2-d imethylcyclo- propane (Table l). The structure of the main product of the decomposition was shown to be 1-isopropylidene-2,2-dimethylcyclopropane by ozonolysis to acetone in 45^ yield. A strong absorp tion band at in the infrared spectrum (Fig. 23) is characteristic of the exomethylenecyclopropane type double bond vibration. The nuclear magnetic resonance spectrum (Pig. 53) and the elemental analysis are consis tent with the 1-isopropylidene-2,2-dimethylcyclopropane structure.

Anal. Calcd. for C, 87.27; H, 12.73 Found; 0, 87.45; H, 12.62 In a typical decomposition, 0.833 g. of the salt of 2,2,4,4-tetramethylcyclobutanone tosylhydrazone was pyrolyzed to give 0.262 g. of diazo compound (72^). This diazo compound was decomposed in a gas chromatograph to give 0.134 g. (46$^ with respect to salt, 64^ with respect to diazo compound) of isopropylidene-2,2-dimethylcyclo propane . 109 Standards

DlcyclopropylcartoInol Cyolopropyl ketone (44 g., 0.4 mole) was added over a period of 1.5 hours to a stirred solution of lithium aluminum hydride (6.0 g., 0.l6 mole) In 250 ml. anhydrous ether. The reaction mixture was held at reflux for one additional hour, then cooled to room temperature. Excess hydride was decomposed by careful addition of water, then 10^ aqueous sodium hydroxide (150 ml.) was added. The ether layer was decanted from the aluminum salts and dried over anhydrous sodium sulfate. The ether was removed by distillation, and the residue was distilled to give 37 g. (82^) of dicyclopropylcarbinol, b.p. 77 -7 8 °/2 7 mm. (Pig. 24).

DicyclopropyImethyl methyl ether Sodium (0.55 g., 0.025 mole) was added to dicyclopropylcarbinol (5.6 g., 0.05 mole). The mixture was o stirred at 70 overnight. The reaction flask was cooled in an ice bath, and methyl iodide (Columbia Organic, not purified) (3.6 g., 0 .0 2 5mole) was carefully added. Stirring was continued for one hour after addition. The dicyclopropyImethy1 methyl ether was distilled from the reaction mixture under vacuum and used as a gas chromato graphic standard without further purification. The infra red spectrum (Pig. 25) has bands at 9.19 (0-0-0), 9.82 110 (cyclopropane), 11.70 (cyclopropane), 12.05/f (cyclopro pane), and no absorption in the OH region.

Reagents and Solvents

Boron trifluoride etherate (Eastman white label) was distilled from calcium hydride under reduced pressure shortly before use. n-Butyl1ithium (Foote Mineral Company) was used as a 1 5.05^ solution in hexane.

2-Cyclohexen-1-one (Aldrich Chemical Co., Inc.) was used without further purification.

Cyclopropyl methyl ketone (Aldrich Chemical Co., Inc.) was used without further purification. Cyclopropyl phenyl ketone (Aldrich Chemical Co., Inc.) was used without further purification. Cyclopropyl cyanide (Aldrich Chemical Co., Inc.) was used without further purification. Diethyl Carbitol (Union Carbide Chemicals Co.) was stored over potassium hydroxide pellets. Shortly before use the diethyl Carbitol was decanted and then distilled, b.p. 188°. Diglyme (Ansul Chemical Co.) was distilled from calcium hydride shortly before use, b.p. l62°.

Dimethyl sulfoxide (Crown Zellerbach) was stored over calcium hydride, and filtered immediately prior to use. Ill Dlmethylformamlde (Eastman white label) was distilled shortly before use, b.p. 152-154°. Lithium aluminum deuteride (Metal Hydrides Co.) of supposedly lOC^ purity was used. Lithium aluminum hydride (Metal Hydrides Co.) of better than 95^ purity was used. Maleic anhydride (Eastman white label) was used without further purification. Mesityl oxide (Eastman white label) was used without further purification. N-Methylpyrrolidone (General Aniline and Film Corp.) was distilled shortly before use. Quinoline (Eastman white label) was used without further purification. Sodium borohydride (Matheson, Coleman, and Bell) of 98^ purity was used. Sodium hydride (Metal Hydrides Co.) was used as a 53.6^ dispersion in mineral oil. Sodium Methoxide (Matheson, Coleman, and Bell) of better than 95^ purity was used. Tetrahydrofuran (Dupont) was stored over potàssium hydroxide pellets. Shortly before use the tetrahydrofuran was decanted and then distilled from calcium hydride. APPENDIX I Tables

112 113 TABLE I

Vacuum Pyrolysis of the Sodium Salt of Cyclopropyl Ketone Tosylhydrazone

Hydrocarbon products (Percentage composition by (Percentage composition gas chromatography)®-® by isolation)®

c 3 » i H > » 1 5) 0 1 m 0 t H C r H r H Ü r H > » a ) > » 0) > » P,*H P 4 P»*H A 0 « d 0 0 * 0 0 Sh Cd U k (d U O i - P O r O r - P A 0 3 0 0 3 0 r H f t r H i H ^ i H 0 0 0 0 k > > I 01 01 01 01 Typical 5 CVJ r H CVl r H Runs_____

1 1 7 93 2 14 86 17 83 3 trace 15 85 21 79 4 2 23 75 24 76 5 1 25 74 24 76 6 2 6 92 7 1 3 96 (a) Gas chromatographic analyses and preparative separations were carried out at 70 on a 3 /8 in. x 1 ft, 20^ SE-30 silicone rubber column, (b) Typical gas chromatogram. Pig. 6 5. 114 TABLE 2 Vacuum Pyrolysis of the Sodium Salt of Cyclopropane- carboxaldehyde Tosylhydrazone

Hydrocarbon products (Percentage composition by (Percentage composition gas chromatography)"® by NMR)^

o 0) Ü G (D d> (d •p td P p* •p G 3 p pj P o p o •91 iH 1 1—1 CO O CO o .< .> t» iH o 1—1 u Run 1 62 38 2 6l 39 3 6l 39 62 38 (a) Calculated from the relative peak areas of absorption due to protons at the 3 and 4 positions of cyclobutene compared with the absorption due to protons at the 1 and 4 positions of 1,3-butadiene (Pig. 43), (b) Gas chromato graphic analyses were carried out at room temperature on a 1/4 in. x 10 ft. 23^ Dowtherm A column, (c) Typldal gas chromatogram. Pig. 73. (d) The gas chromatographic retention time was identical to that of a pure authentic sample of 1,3-butadiene. 115 TABLE 3

Pyrolysis of the Sodium Salt of Cyclopropanecarboxaldehyde Tosylhydrazone at Atmospheric Pressure

Hydrocarbon products (Percentage composition by gas chromatography)®®

T) 0) c 0) Q) 0 •H C .a 0) i P 0 >* P 1 r H Xi 0> 0 0 0 ■ P 0 •» Î» (U (d r H 0 Run 1 (only 1,3-butadiene observed)® 2^ 12 10 52 26 3^ 13 10 44 33 (a) Gas chromatographic analyses were carried out at room temperature on a 1/4 in. x 10 ft. 235^ Dowtherm A column, (b) Gas chromatographic retention time was identical to that of an authentic sample of ethylene. (c) Gas chromatographic retention time was identical to that of an authentic sample of acetylene, (d) Gas chromatographic retention time was identical to that of an .authentic sample of 1,3-butadiene, (e) No hydro carbons of longer retention times were observed even using a 3/8 in. x 10 ft. 23^ ^,P'-oxydipropionitrile column at room temperature, (f) Typical gas chromato gram, Pig. 66. (g) The infrared spectrum (Pig. 26) of this gaseous reaction product was identical to that of a pure authentic sample of 1^3-butadiene. 116 TABLE 4

Decomposition of Cyclopropanecarboxaldehyde Tosyl hydrazone In Diethyl Carbitol at 180®

Hydrocarbon products (Percentage composition by gas chromatography)

> ,Q 0 0 0> •p 1 f H >» r H 0 0 0 0 0 0 •» Ti i 1 w cd i H 0 P

0.78 7 4 6 26 57 1.75 9, 8 39 _ 41 3 0 (a) 21 5^ 69 (a) The small yield of hydrocarbons did not allow analysis of the ethylene formed, nor determination of the individual percentages of cyclobutene or 1,3-butadiene, (b) These structures were assigned by comparison of their retention times with those of authentic samples. 117 TABLE 5

Decomposition of the Sodium Salt of Cyclopropane carboxaldehyde Tosylhydrazone at 180°

Hydrocarbon products (Percentage composition by gas chromatography)

u o o f—tA3 0) o c (D rH ra a O •H C 3 >> O rH X rH » -9 O O > 0) >» 1 rH pH XÎ Xi » ■H 01

DEC (a) 14 35 41 10 DEC 7 8 32 34 16 DEC (10^ EG) 8 28 64 DEC (1.25$^ HpO) 10 4 3 50 33 EG 6 15 74 (a) Ethylene analysis was not carried out on this sample. (B) DEC = diethyl Carbitol; EG = ethylene glycol, (c) These structures were assigned by comparison of their retention times with those of authentic samples. 118 TABLE 6

Vacuum pyrolysis of the Sodium Salt of 1-Phenylcyclo- propanecarhoxaldehyde Tosylhydrazone

Hydrocarbon products (Percentage composition by gas chromatography)®

bO 0) bO t» > » r H 0 1 (U r H r H 0 (d & s& r H a A

Hydrocarbon products (Percentage composition by gas chromatography)

< I pq Ü p +5% C is c C û s I g CO o b o I 5 S 5 •> CVJ Run

i L 77 2 3 18 2%G 1 72 6 2 4 16 3°^ 1 81 4 1 2 11 (a) Gas chromatographic analysis was conducted at 75° on a 1/4 in. x 5 ft. 20$ SE-30 silicone rubber column. (b) Gas chromatographic analysis was carried out at 49° on a 1/4 in.. x 5 ft. 23$ ^,^-oxydipropionitrile column. (c) Gas chromatographic analysis was effected at 55° on a 1/4 in. x 5 ft. 30$ SE-30 silicone rubber column. (d) Preparative gas chromatographic separations were carried out at room temperature on a 3/8 in. x 10 ft. 23$ (3ig^'-oxydipropionitrile column, (e) Typical gas chroma togram, Pig. 68. (f) The nuclear magnetic resonance spectrum (Fig. 5^) and the infrared spectrum (Pig. 28) of a pure sample are consistent with the assigned structure, (g) The nuclear magnetic resonance spectrum (Pig. 55), the infrared spectrum (Pig. 29), and the gas chromatographic retention times of a pure sample were identical to those of a pure authentic sample of 2,4-dimethy1-1,3-pentadiene (obtained from Dr. K.W. Greenlee). 120 TABLE 8

Vacuum Pyrolysis of the Sodium Salt of Methyl 2- Methylcyclopropyl Ketone Tosylhydrazone

Hydrocarbon products (Percentage composition by gas chromatography)^^ p 0 Q) 0> c q d> 0) *d •H •H % % 0 0) p P G a q q 0 0 .» U u rH (M PP p Run

1 7 32 8 2 03 5 9 3 1 38 10 30 12 (a) Gas chromatographic analyses and preparative separa tions were carried out at room temperature on a 3 /8 in. x 10 ft. column of 23^ ^j^'-oxydipropionitrile. (b) The infrared spectrum (Pig. 30) and the gas chromatographic retention time of a pure sample were identical to those of a pure authentic sample of trans-2-methy1-1,3-pentadiene (obtained from Dr. K.W. Greenlee). (c) The gas chroma tographic retention time was identical to that of a pure authentic sample of trans-3-methyl-1,3-pentadiene (obtained from Dr. K.W. Greenlee). (d) A poor gas chromatographic separation of this mixture into its components could be obtained at room temperature on a 100 ft. squalene capillary column, (e) The infrared spectrum (Pig. 31) of this fraction shows bands at 5 .5 5 (zCHg), 6 .0 8 (0=0), 1 0 .1 0 (OHzOHg), and 11.20/( (gOHg), which could be consistent with cis-2-methyl-1,3-pentadiene. (f) Typical gas chromato gram, Pig. 6 9. 121 TABLE 9

Vacuum Pyrolysis of the Sodium Salt of Blcyolo[4,1.0]- 2-heptanone Tosylhydrazone

Hydrocarbon products (Percentage composition^by (Percentage composition gas chromatography) by isolation)^

32 (U G G <0 p p A A 32 V Si Xi 1 1 CVl CVl 0 1 1 0) 1—1 <0 1— 1 0 0 £ R I fH r rH KÛ » VO 1 1 c 1_ 1 c 1_ 1 a> 0 0) 0 •p rH p rH A 0 A 0 % 0> A 0 Xi 0 1 •H T •H iH r4 A Run 1 16 84 2 17 83 16 84 3 18 82 17 83 (a) Gas chromatographic analyses and preparative separations were carried out at 80° on a 1/4 in. x 5 ft. 20^ SE-30 silicone rubber column, (b) Typical gas chromatogram. Pig. 70. (c) The infrared spectrum (Fig. 32) and the nuclear magnetic resonance spectrum (Pig. 5 6) of a pure sample are consistent with the assigned structure, (d) Upon heating the injection port of the gas chromatograph to 350 , very little change in relative or absolute peak areas was noted. 122 TABLE 10

Vacuum Pyrolysis of the Sodium Salt of Cyclopropyl Methyl Ketone Tosylhydrazone

Hydrocarbon products (Percentage composition by (Percentage composition gas chromatography) by isolation)

TJ > 1— 1 o o 1 rH O 1 rH r—1 rH O rH rH Ü >» k XibX bO XX b O -p p rH P p rH 0 ) 0 ) b 0 ) 1— 1 CVl > Run

1^ 35 33 32 36 36 28 26 43 31 34 36 30 33 36 31 31 38 31 I. 32 40 28 (a) Gas chromatographic analysis was carried out at room temperature on a 1/4 in. x 5 ft. 23^ $,^'-iminodipropionitrile column, (b) Gas chromatographic analysis and preparative separations were effected at room tempera ture on a 3/8 in. x 10 ft. 23^ ^-oxydipropionitrile column, (c) The nuclear magnetic resonance spectrum of a pure sample. Pig. 57• The infrared spectrum of a pure sample (Pig. 33) was in excellent agreement with the literature (3b). (d) The nuclear magnetic resonance spectrum (Pig. 58), the infrared spectrum (Pig. 34), and the gas chromatographic retention times of a pure sample were identical to those of authentic 2-methyl-1,3-butadiene (e) The nuclear magnetic resonance spectrum (Pig. 59), the infrared spectrum (Pig. 35), and the gas chromatographic retention times of a pure sample were identical with those of authentic vinylcyclopropane (obtained from Dr. K.W. Greenlee), (f) Typical gas chromatogram. Pig. 71. 123 TABLE 11 Vacuum Pyrolysis of the Sodium Salt of 2,2,4,4-Tetra- methylcyclobutanone Tosylhydrazone and Decomposition of the Intermediate Diazo Compound

Hydrocarbon products (Percentage composition by gas chromatography)

I < M < D cvi Cd I A d> o C k 0) A "O O • H f H rH o pq A O Ü O rH

OS O -P o i

r H ' d Run

L 2 20 75 3 2° 2 13 84 1 3 4 14 83 4 3 17 7 8 2 (a) Gas chromatographic analyses and preparative separations were carried out at 5 0° on a 1/4 in. x 5 ft, 20^ SE-30 silicone rubber column, (b) Typical gas chromatogram. Pig. 72. APPENDIX II Infrared Spectra

124 125

4 0 0 0 3000 2000 1500 700 KX)K»r.ri... r O O

8 0

i40

20 -10

WAVELl FjGURE

I 4 0 0 0 3000 2000 1500 looo 9 9 0 8 90 700 100 . 00

^60

i40

20 :|0

FIGURE 2

CM-' 4 0 0 0 3000 2000 1500 1000 990 700 100 . 00

60 2% o -3S i40 4 z 5m 20 :|0

WAVELl FIGURE 3 126

4000 3000 2000 1500 100 . rOO

60 ■2^ o

i40 1 -5m 20 :|0

FIGURE 4

CM- 4000 3000 2Q00 1500 looo 9 9 0 8 9 0 700 100 . 0.0

80 ;— \

2% o 33 4 z 5m 20 :|0

r 8 9 10 FIGURE 5 WAVELENGTH (MICRONS) I 4000 3000 2000 1500 iqoo 990 890 7 00 100... •0,0

:60

140

20 :|.0

FIGURE 6 127

40003000 2000 1500 1000 9Ç0 SÇO 100-

8 0

160 -2^ i40 î 2Œ -10

WAVEÜ F|6URE 7

I 4000 3000 2000 1500 iqoo 9 9 0 8 9 0 7 0 0 100.. rOO

160

(40

20 -10

WAVE! FIGURE 8

CM-' 4000 3000 2000 I5Q0 iqoo 9 9 0 8 9 0 7 0 0 100 . 00

■2^ -3§ 4 z -5m 20 :|0

WAVELl FIGURE 9 128

2000 1500 0.0

!60 2m

20 :|0

FIGURE 10 I

4 0 0 0 3 0 0 0 2000 1500 700 100 . — — rOO

160 -4 i40

20 -10

WAVEI FIGURE I 4 0 0 0 3 000 2QOO 1500 IQOO 990 890 lOO .

80 60 -4 i4 0 â 20 -10

FIGURE 12 129

2000 1500 00

8 0 î 20 -10

FIGURE 13 I 4 0 0 0 3000 2Q00 1500 700 Kxn. 00

'60 i40

20 :|0

FIGURE 14

CM 4 0 0 0 3000 2000 1500 700 100 H . 00

160 % 140- 4 z 5m

:|0

WAVElil;NGTH (MICRI FIGURE 15 130

4 0 0 0 3 0 0 0 2000 1900 100-““““*^ 00

8 0

20 :10

FIGURE 16 I 4 0 0 0 3000 2Q00 1500 100 . 00

60 -20D i40

20 :10

FIGURE 17 I 4 0 0 0 3 000 2Q00 1500 100 . rOO

8 0

60 i40

FIGURE 18 131

4 0 0 0 3 0 0 0 2000 1500 7 0 0 100.... — rOO

160 i40 -5m 20 -10

WAVELl FIGURE 19

4 0 0 0 3000 2QOO 1500 iqoo 9 9 0 8 9 0 7 0 0 K30W‘“^"‘‘“ rOO

8 0 '

!eo

FIGURE 20

CM-' 4 0 0 0 3000 2000 1500 iqoo 990 890 7 00 100 . 00

160 i4 0

20 10

WAVEI FIGURE 21 132

2QOO 1500 IQOO 990 890

8 0

'6 0 i4a

2a :|0

FIGURE 22 I cw 4 0 0 0 3 0 0 0 2000 1500 iqoo 990 890 700 100 ‘ rOO

i40

:|0

WAVELl FIGURE 23 I CM-' 4 0 0 0 3000 2Q0O 1500 IQOO 990 ago 700 loo-h***—^ 00

8 0

60 -2% o

i40 -42 -,5m 20 :|0

WAVEl^NGTH%ICR^SI FIGURE 24 133

4 0 0 0 3 0 0 0 2000 1500 100.. 00

8 0 j e o y i4a

20 -6 -10

FIGURE 25 I CM-" 4 0 0 0 3000 2000 1500 100 - 00

8 0

160 i40 I 20-

FIGURE 26

CM-* 4 0 0 0 3000 2000 1500 100 .

8 0

60 i40

20 :10

FIGURE 27 134

4 0 0 0 3 0 0 0 2000 1500 100 . 00

160 o i4a i :10

WAVEI FIGURE 28

CM-* 4 0 0 0 3000 2QOO 1500 IQOO 990 890 700 100 . r O O

8 0

GO -.200 I i4a .4z ,5m 20 :|0

WAVELl FIGURE 29

OM- 4 0 0 0 3000 2Q00 1500 IQOO 990 890 700 100 . 0.0

8 0

60 -2m ■ 4 i40 -4 z -,5m

:|0

WAVEI&NGTH%ICR&IS) FIGURE 30 135

1500 iqoo 9 9 0 8 902000 rOO

160 i4a

:|0 è ■ è ' I ' à ' 9 ' lb ' 3 I WAVELENGTH (MICRONS) FIGURE 31 I 4000 3000 2000 1500 iqoo 9 9 0 ago 700 100 . 0 0

60 i40

:|0

WAVELl FIGURE 32 I 4000 3000 2000 1500 700 100 . 00

60 -2% - 4 ;40 -4z -5m 2a -10

WAVEI FIGURE 33 136

1004 0 0 0 3COOI".. 2000 1500 iqoo 9 9 0 8 9 0

i40 - 4 z -5m

:10

FIGURE 34 CM-* 4 0 0 0 3 000 2Q00 1500iqoo 9 9 0 8 9 0 7 0 0 100 . — rOO

8 0

3 -5m 2a

FIGURE 35 APPENDIX III Nuclear Magnetic Resonance Spectra

137 1 0 FIGURE 36 (Tau)

M w 00 FIGURE 37 (Tau)

M W VO 1 0 FIGURE 38 (Tau)

4r O Hhi

1 0 FIGURE 39 (Tau) 1 0 FIGURE 40 (Tau)

M fO 1 0 FIGURE 4 (Tau) I

w 1 0 FIGURE 4 (Tau)

•*=■H •tr , » » ywi 10 FIGURE 43 (Tau)

M 4r VJl 1 0 FIGURE 44 (Tau)

a\ 4 5 6 7 8 9 10 FIGURE 4^ (Tau)

Hfr -q 10 FIGURE 46 (Tau)

M 00 10 FIGURE 47 (Tau)

M VO 10 FIGURE 48 (Tau)

O 10 FIGURE 4 (Tau)

H» VJl FIGURE 5Ô (Tau)

H VI to 10 FIGURE 5 (Tau)

H VJ» CO 10 FilGURE 52 (Tau)

ui f FIGURE 5 (Tau)

ui ui 10 FIGURE ^ (Tau)

ui o% FIGURE 55' (Tau)

H UI FIGURE s i (Tau)

\ j i CO 159

VO «J

ce vD wn*^n» » h > MiHMyw k yWi^*W4#*i^# WW V %i k 10 FIGURE sl (Tau)

o\ o FIGURE si

o\ H APPENDIX IV Ultraviolet Spectra

162 0.0

M I 9

1.0

1.2

250 300 350 S. 200 WAVELENGTH U) FIGURE 60 (MILLIMICRONS) o.a

0.2

1.0

1.2

200 250 WAVELENGTH 300 350 S FIGURE 6l (MILLIMICRONS) APPENDIX V

Near-Infrared Spectrum

165 0.9

If 700 o\ FIGURE 62 WAVELENGTH (MILLIMICRONS) APPENDIX VI

Gas Chromatograms

167 00

cr» U) dlcyclopropylmethyl £-tolyl suifone

00 1-cyclopropyIcyolobutene

etner air

RECORDER RESPONSE 89t CO

12 10 8 6 RETENTION TIME (MINUTES) FIGURE 64 VO

o\ -cyc iopropylcyclobutene

2-cyclopropyl-l,3-butadlene

air

RECORDER RESPONSE

Oil - p

r i COI

0 1

10 8 6 4 2 0 RETENTION TIME (MINUTES) FIGURE 66 I"4 o\ -c

1-phenylcyclobutene

3 -C 2-phenyl-1,3-butadlene

03 phenylacetylene air

o -

RECORDER RESPONSE

Si.T 4 Q 2,4-dimethyl-1,3-pentadlene

— — ^ attenuation 5 00 1,3,3-trlmethylcyclobutene

w 03

air

RECORDER RESPONSE £Ll *3d g

ON trans-3-methyl-1,3-pentadlene

trana-2-methyl-1,3-pentadiene

I M H3

1-3

00 CO

If3-dimethyIcyclohutene and 2,3-dimethyloyolobutene

air

RECORDER RESPONSE VD

6 4 2 0 RETENTION TIME (MINUTES) FIGURE 70 «H

t H r H

M 6 4 2 \ 0 PIQURE 71 RETENTION TIME (MINUTES) I o iH O 0) kg m o a) a S! I +5 P i - P

-P

iH !co S

•H i I

12 RETENTION TIME (MINUTES)

FIGURE 72 no g H CO

o Ü

-4 12 00 FIGURE 73 RETENTION TIME (MINUTES)