Reactions of Gem-Dihalides with Metals

This dissertation has been 61-5124 microfilmed exactly as received

SHANK, Raymond S., 1931- REACTIONS OF GEM-DIHAUDES WITH METALS.

The Ohio State University, Ph.D., 1961 Chemistry, organic

University Microfilms, Inc., Ann Arbor, Michigan REACTIONS OF GEM-DTHALIDES

WITH METALS

DISSERTATION

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

RAYMOND S. SHANK, B.Sc., M.Sc.

The Ohio State University

1961

Approved by

Adviser Department of Chemistry ACKNOWLEDGMENT

T would like to express my deep appreciation to

Professor Harold Shechter for proposing this study, for his helpful guidance and timely suggestions throughout its investigation, and for the many hours he so unselfishly gave during the preparation of this manuscript.

The chemicals and gas chromatographic information furnished by Dr, Lester Friedman as well as the authentic hydrocarbons which were obtained from Dr. K. W. Greenlee,

Dr. A. J_. Streiff, and Vincent Wiley for gas chromatographic comparisons are also acknowledged. The equipment supplied by, the discussions with, and the suggestions of fellow graduate students were helpful and appreciated.

Finally, I am indebted to the Department of

Chemistry for affording me the opportunity as a Teaching

Assistant to obtain additional training and experience. I am also grateful for financial assistance furnished by funds made available from The Ohio State University Develop ment Fund, the Petroleum Research Fund of the American

Chemical Society, and the National Science Foundation.

ii CONTENTS

PART I

REACTIONS OP ZINC-COPPER COUPLE AND GEM-DIHALIDES

IN PRESENCE OP UNSATURATED COMPOUNDS

Page

INTRODUCTION AND HISTORICAL ...... 2

DISCUSSION...... 8

EXPERIMENTAL...... 16

General Information ...... 16 M a t e r i a l s ...... 16 Gas Chromatography...... 17 Intermediates...... 19

Zinc-Copper Couple ...... 19 1.1-Diiodoethane ...... 19

Reactions of Methylene Iodide, Zinc-Copper Couple, and O l e f i n s ...... 20

, General Procedure ...... 20 Bicyclo[4.1,£>]heptane from Cyclohexene ...... 22 n-Hexylcyclopropane from 1-Octene ...... 23 1-Methyl-4-(1-methylcyclopropyl)cyclohexene from (+)-Limonene ...... 26 2-0xabicyclo[4.1.0]heptane from Dihydropyran . . 26

Unsuccessful Reactions of 1,1-Dihalides, Zinc- Copper Couple, and Unsaturated Compounds.... 27

Methylene Iodide, Zinc-Copper Couple, and Diphenylacet^lene...... 27 Methylene Iodide, Zinc-Copper Couple and 2-Pentyne...... 28 Methylene Bromide and Zinc-Copper Couple.... 29 1.1-Dichloroethane, Zinc-Copper Couple, and Cyclohexene ...... 29 1.1-Diiodoethane, Zinc-Copper Couple, and Cyclohexene ...... 3°

iii iv

CONTENTS (Continued)

PART II

REACTIONS OP METALS AND GEM-DIHALIDES

Page

INTRODUCTION ...... 32

HISTORICAL...... 35

SUMMARY ...... 47

DISCUSSION...... 50

Preparation of gem-Dihalides ...... 50 Reactions of gem-Dlhalldes and Metals...... 56

EXPERIMENTAL ...... 83

Special Techniques ...... 83 Preparation of gem-Dlhalldes ...... 83

0(. -Bromobutyryl Bromide ...... 83 oC -Bromobutyramide...... 84 1.1-Dibromopropane ...... 85 1.1-Dibromobutane ...... 86 1.1-Dichlorobutane ...... 88 1.1-Dichloropropan e ...... 89 1.1-Dichloro-2,2-dimethylpropane (l,1-Di- chloroneopentane)...... 90 1.1-Dichlorocyclobutane ...... 91 1.1-Dichlorocyclopentane ...... 92 1.1-Dichlorocyclohexan e ...... 94 1.1-Dlchlorocyclooctane...... 96

R e a g e n t s ...... 97 Sodium Dispersion...... 99 Reactions of gem-Dihalides and Metals...... 100

General Technique ...... 100

Sodium...... 100 Magnesium ...... 101 Zinc-Copper Couple...... 102 V

CONTENTS {Continued)

Page

Analytical Procedure . . • ...... 102

Gas Chromatography ...... 102 Yield of Products ...... 105

Reaction of 1,l-Dichloro-2,2-dimethylpropane with Metals ...... 106 Reaction of 1,1-Dichlorocyclobutane with Metals. 108 Reaction of 1,1-Dichlorocyclopentane with S o d i u m ...... 110 Reaction of 1,1-Dichlorocyclohexane with Sodium. Ill Reaction of 1,1-Dichlorocyclooctane with Sodium. Ill

Attempted Isomerizations with Sodium ...... 113

Cyclooctene ...... 113 Bicyclo[5.1.0]octane ..... 113

Introduction to Tables ...... 114 LIST OF TABLES

Table Page

1. Reactions of Olefins with Methylene Iodide and Zinc-Copper Couple ...... 9

2. Summary of Yields and Physical Properties of gem-Dlhalldes...... 51

3. Summary of Reactions of 1,1-Dibromoethane with M e t a l s ...... 57

4. Summary of Reactions of 1,1-Dihalopropanes with Metals ...... 59

5. Summary of Reactions of 1,1-Dihalobutanes with Metals...... 65

6. Summary of Reactions of 1,l-Dichloro-2,2- Dimethylpropane with Metals...... 69

7. Summary of Reactions of 1,1-Dichlorocyclo butane and Metals...... 76

8. Reactions of 1,1-Dibromoethane with Metals . . 115

9. G. P. C. Analyses of Products from Reactions of 1,1-Dibromoethane with Metals ...... 116

10. Reactions of 1,1-Dihalopropanes with Metals. . 118

11. G. P. C. Analyses of Products from Reactions of 1,1-Dihalopropanes with Metals...... 119

12. Reactions of 1,1-Dihalobutanes with Metals . . 121

13. G. P. C. Analyses of Products from Reactions of 1,1-Dihalobutanes with Metals ...... 122

14. Reactions of l,l-Dichloro-2,2-dimethylpropane with Metals...... 125

vi vii

LIST OP TABLES (Continued)

Table Page

15. G. P. C. Analyses of Products, from Reactions of l,l-Dichloro-2,2-dimethylpropane with M e t a l s ...... 126

16. G. P. C. Analyses of High-Boiling Products from Reactions of 1,l-Dichloro-2,2-dimethylpropane with Metals...... 130

17. Reactions of 1,1-Dichlorocycloalkanes with Metals ...... 132

18. G. P. C. Analyses of Products from Reactions of 1,1-Dichlorocyclobutane with Metals . . . 133

19. G. P. C. Analyses of Products from Reactions of 1,1-Dichlorocyclopentane and 1,1-Di chlorocyclohexane with S o d i u m ...... 137

20. G. P. C. Analyses of Products from Reaction of 1,1-Dichlorocyclooctane with Sodium . . . 139

21. G. P. C. Analyses of Products from Treatment of Blcyclo[5.1.0]octane with Sodium..... 142 LIST OP FIGURES

Figure Page

1. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dibromoethane with M a g n e s i u m ...... 117

2. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichloropropane with M a g n e s i u m ...... 120

3. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichloropropane with S o d i u m ...... 120

4. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dibromopropane with M a g n e s i u m ...... 120

5. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dibromobutane with Zinc- Copper ...... 124

6. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichlorobutane with M a g n e s i u m ...... 124

7. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichlorobutane with S o d i u m ...... 124

8. Gas Chromatograms of Hydrocarbons from Re actions of 1,l-Dichloro-2,2-Dimethyl- propane with Metals...... 128

9. Gas Chromatograms of Hydrocarbons from Re actions of l,l-Dichloro-2,2-Dimethyl- propane with S o d i u m ...... 129

10. Gas Chromatogram of High-Boiling Hydro carbons From Reaction of 1,1-Dichloro- 2.2-Dimethylpropane with Sodium. .... 131

11. Gas Chromatogram of High-Boiling Hydro carbons From Reaction of 1,1-Dichloro- 2.2-Dlmethylpropane with Sodium. 131

viii ix

LIST OP FIGURES (Continued)

Figure Page

12. Gas Chromatograms of Hydrocarbons from Re actions of 1,1-Dichlorocyclobutane with Metals...... 135

13. Gas Chromatograms of Hydrocarbons from Re action of 1,1-Dichlorocyclobutane with M a g n e s i u m ...... • 136

14. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichlorocyclohexane with Sodium...... 138

15. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichlorocyclopentane with S o d i u m ...... 138

16. Gas Chromatogram of Hydrocarbons- from Re action of 1,1-Dichlorocyclooctane with Sodium...... 141

17. Gas Chromatogram of Hydrocarbons from Re action of 1,1-Dichlorocyclooctane with Sodium...... l4l PART T

REACTIONS OF ZINC-COPPER COUPLE AND GEM-DIHALIDES

IN PRESENCE OF UNSATURATED COMPOUNDS

1 INTRODUCTION AND HISTORICAL

Cyclopropane derivatives have received increased attention in the last few years from both theoretical and synthetic viewpoints. However, most of the methods for preparing cyclopropanes possess distinct disadvantages.

A general approach for synthesis of cyclopropanes involves addition of a divalent carbon intermediate to a carbon-carbon double bond. This concept has been utilized in the classical reaction of aliphatic diazo compounds with olefins (l) and in addition of dihalocarbenes to

(1) For a review of the chemistry of diazo com pounds and bivalent carbon see R. Huisgen, Angew. Chem., 61, 439 (1955). carbon-carbon double bonds (2). Additions of dihalo-

(2)(a) W. von E. Doering and A. K. Hoffman, J. Am. Chem. Soc., 76, 6162 (1954); (b) P. S. Skell and A. Y. Garner, ibid.. 3409, 5430 (1956); (c) W. von E. Doering and P. La Flamme, ibid., 78, 5447 (1956). carbenes or methylene to olefins occur stereospecifically by els processes. Thus, cls-2-butene gives derivatives of cis.-1,2-dimethylcyclopropane, whereas trans-2-butene yields trans-1,2-dimethyl derivatives (2b)(3b). Addition of a methylene group to an olefin has been accomplished from intermediates generated from photolysis of ketene or diazomethane (3). Methylene derived from photolysis is

(3)(a) W. von E. Doering, R. G. Buttery, R. G. Laughlin, and N. Chaudhuri, J. Am. Chem. Soc., j[o, 3224 (1956); (b) P. S. Skell and R. C. Woodworth, ibid.. J 8, 4496 (1956); (c) H. M. Prey, ibid.. 80, 5005 (1958TTT^) J- H. Knox and A. P. Trotman-Dickenson, Chem. and Tnd. (London), 1039 (1957). very reactive (3c) (3d) and does not discriminate between olefinic and carbon-hydrogen bonds. As a result of random insertion, reactions of olefins with methylene generated in this manner give large amounts of difficulty separable, isomeric hydrocarbons along with the desired cyclopropanes

(2 c)(3a ) .

It has recently been reported that olefins react with methylene iodide and zinc-copper couple to give cyclopropanes (4). This reaction is satisfactory for

(4) (a) H. E. Simmons and R. D. Smith, J. Am. Chem. Soc., 80, 5323 (1958); (b) Ibid.. 8l, 4256 (1959). stereospecific addition of a methylene group to an olefin to give the corresponding cyclopropane in good yield. No insertion between carbon-hydrogen bonds has been observed

(4). This synthetic method is general in that it is applica ble to hindered olefins; olefins substituted with electro negative or electropositive groups also give satisfactory results. Conjugated olefins such as styrene and propenylbenzene function normally in the reaction. The relative amounts of reagents employed determine whether one or two cyclopropyl groups are formed fi*om unconjugated dienes such as 1,5-hexadiene (4).

Reactions between zinc-copper couple, methylene iodide, and dialkylacetylenes occur (4)(5), but with

(5) H. E. Summons, personal communication. much greater difficulty and much less specificity than

those with olefins. Aliphatic acetylenes give mixtures of unidentified products some of which, on the basis of

their infrared absorption, may be cyclopropane derivatives

(4b). However, the use of acetylenes in this reaction has not been thoroughly investigated.

Although no systematic study of the effect of solvents has been made, diethyl ether consistently gave highest yields and most easily controlled reactions (4).

When higher boiling solvents such as ethyl acetate, ethylene glycol dimethyl ether, and tetrahydrofuran were used, a white crystalline compound, methylenedizinc di iodide, was also formed; mixed solvents such as ether and tetrahydrofuran offered no advantages (4).

Detailed investigation of the mechanism of the reaction of olefins with methylene iodide and zinc-copper couple has not been made, but reasonable processes have been suggested (4b). Possible mechanisms based on (A) addition of frt ~ methylene to a double bond, (B) addition of iodomethylzinc iodide as a carbanion to the olefinic bond followed by cyclization by intramolecular displace ment, or (C) homolytic dissociation of iodomethylenezinc iodide and subsequent free radical addition have received little support from theory and experimental observations

(6). A mechanism consistent with the known facts

(6) For a more detailed discussion of these possible mechanisms consult Ref. (4). % 1------pictures iodomethylzinc iodide as a relatively strongly bonded complex of methylene and zinc iodide, the carbon atom of which is electrophilic. Reaction can occur as shown below through a three-center transition state:

v / w \ / C Znl c. Znl C Znl I \ + c h 2; i I > 2 .' , CHc ' * I T C ‘I C / \ A- / \

This mechanism accounts for the stereospecificity observed and, since the transition state includes a molecule of zinc iodide, would make greater steric demands than would tran sition states involving a free carbene (2 a) (2 c ) (3a ). 6

The method for preparing the zinc-copper couple is important with respect to its reactivity with methylene iodide and its reproducibility for preparing cyclopropanes.

The most effective zinc(90$)-copper(10$) couple used pre viously was prepared by reaction of zinc dust, cupric oxide, and hydrogen at 500° (4)(7) and was subsequently

(7)(a) P. R. Howard, J. Research Natl. Bur. Standards, 24, 677 (1940)j (b) P. R. Buck, B. B. Eisner, E. J. Forbes, S. H. Morrell, J. C. Smith, and E. R. Wallsgrove, J. Tnst. Petroleum, 34. 339 (1948). activated by iodine. For purposes of synthesis, this method of obtaining the couple is inconvenient; the ac tivity of the couple is also affected by the temperature at which it is prepared. Couples derived from granulated zinc and copper powder do give cyclopropanes but in erratic yields; those obtained by thermal decomposition of cupric citrate in the presence of zinc dust react difficultly with methylene iodide (4).

The fact that special equipment must be used and precautions must be taken in preparation of the zinc- copper couple are distinct disadvantages of this general method to make cyclopropanes. If a simpler but just as effective zinc-copper couple could be devised, then this synthetic method for preparing cyclopropanes would have greater utility. Therefore, an rttemia v:as made t : adapt the :‘no-aopper couple which had been used 7

successfully in the reduction of propargyl halides to allenes to this synthesis for cyclopropanes (8).

(8)(a) G. P. Hennion and J. J. Sheehan, J. Am. Chem. Soc., £L, 1964 (19^9); (b) R. S. Shank, M. Sc. Thesis, The Ohio State University (1958). DISCUSSION

A study of the utility of a zinc-copper couple in syntheses of cyclopropanes from olefins and methylene iodide has been made. The zinc-copper couple was prepared from zinc dust and aqueous copper sulfate. Previously a more elaborately prepared zinc-copper couple (7) had been used in this reaction (4).

A summary of the reactions of olefins with methylene iodide and zinc-copper couple is contained in

Table 1. The hydrocarbon reaction products were analyzed by gas chromatographic and infrared techniques. The yields In these reactions were determined from distillation data and/or calculations based on results of gas chromato graphic analysis.

Since the overall reproducibility and effective ness of the simplified zinc-copper couple to prepare cyclopropanes was being tested, only representative olefins were used in the investigation. A detailed study which had been made previously shows the scope and variety of olefins which may be successfully used (4).

The simplified zinc-copper couple can be made rapidly by washing zinc dust successively with dilute 8 TABLE 1

REACTIONS OP OLEFINS WITH METHYLENE IODIDE AND ZINC-COPPER COUPLE

Reaction Olefin Olefin CHPIp Zn(Cu) Time Product Per Cent (mol.) (mol.) (mol.) (hr.) Yield

53c,d l-Octenea 0.40 0.20 0.30 19 n-hexylcyclopropane

l-Octenea 0.40 0.20 0.30 67 n-hexylcyclopropane 50c

1-Octene*5 o.4o 0.20 0.25 30 n-hexyIcyclopropane 48c

l-Octenea 0.40 0.25 0.20 48 n-hexylcyclopropane 47c

l-Octenea 0.40 0.20 0.50 41 n-hexylcyclopropane 38°

Cyclohexene8 0.30 0.15 0.22 67 bicyclo[4.1.0 Jheptane 50c*d Cyclohexene8 0.40 0.20 0.30 64 bicyclo[4.1 .0 ]heptane 47°

(+)-Limonenea 0.15 0.30 0.33 70 l-methyl-4-(l-me thy1- cyclopropyl) cyclohexene 5id

Dihydropyran*5 0.15 0.25 0.33 20 2-oxabicyclo[4.1.0]heptane 66°

(a) Reaction was effected by adding a mixture of olefin, methylene iodide, and ether to zinc-copper couple, (b) Reaction was effected by first initiating re action of zinc-copper couple, methylene iodide, and iodine in ether and then adding the olefin in ether, (c) The yield was computed from gas chromatographic data, (d) The reaction product was rectified. 10 hydrochloric acid, water, dilute copper sulfate, absolute ethanol and ether. After the couple is dried, it may be used immediately or else stored without losing.its effectiveness (9).

(9) The exact length of time the zinc-copper couple can be stored before it becomes ineffective has not been determined.

Most of the preparations of cyclopropanes could be effected simply by refluxing a stirred mixture of methylene iodide, zinc-copper couple, and the olefin in anhydrous ether. The general precautions that are taken with

Grignard reactions were followed. It appears unnecessary however to exclude oxygen from the reaction, since no differences were noticed when reactions were run with air present. Iodine was used as an initiator in most of the reactions but it appears that this is not needed, although it might reduce the length of the induction period slightly.

It was not possible to initiate reaction of dihydropyran, methylene iodide, and zinc-copper couple in refluxing ether. The procedure was modified by first adding methylene iodide to the zinc-copper couple in ether; after reaction had started, a solution of dihydropyran in ether was added. After these changes had been incorporated in the synthesis, no further difficulties were encountered in the initiation step.

It is advantageous to initiate reaction of methylene iodide with zinc-copper couple previous to addition of the olefin (as was the case with dihydropyran) rather than to combine all the reactants at the outset.

This allows for easier initiation and shortens the overall reaction time. In comparable experiments with 1-octene in which different initiation techniques were used, the yields of n-hexylcyclopropane were practically the same (Table l).

The reaction time necessary to obtain an optimum yield of a cyclopropane has not been determined; to compare the effectiveness of the simplified zinc-copper couple with the more elaborate one, the same experimental conditions described by Simmons and Smith (4) were maintained. Long reaction times do not increase the yields of the cyclo propanes (Table 1); the reaction is essentially complete after 4-6 hr. The exact time necessary for reaction is of course influenced by factors such as steric hindrance and the electron density at the double bond undergoing re action.

When the crude reaction mixtures were filtered to remove excess couple and precipitated zinc iodide and then were hydrolyzed, large volumes of gas, probably methane, were evolved. It is postulated that two species of organometallic intermediates, ICHgZnI and CHgfZnIare formed in reaction of methylene iodide and zinc-copper couple, but that only ICHgZnI reacts with olefins to form cyclopropanes; the other organometallic CH2 (Znl)2 may not react with olefins but gives methane upon treatment with water. This hypothesis is supported by the following facts: (A) The yield of n-hexylcyclopropane remains the same although the reaction time is increased by a factor of

3.5 (Table l). Since 1-octene and zinc-copper couple are both present in excess, it is expected that the yield would increase unless methylene iodide was being removed by a competitive reaction, for example the formation of

CH2 (Znl)2 . (B) When the amounts of methylene iodide and

1-octene are kept constant but the quantity of zinc-copper couple is doubled, the yield of the cyclopropane is de creased from 48 to 38/0. If a large excess of the couple were present, it would be expected that more CH2 (Znl)2 would be formed relative to ICH2 ZnI, and as a result less n-hexylcyclopropane would be produced. (C) It has been previously reported that white crystalline CH2 (Znl)2 was formed when higher boiling solvents such as ethyl acetate, ethylene glycol dimethyl ether, or tetrahydrofuran were used in the reaction with zinc-copper couple, methylene

Iodide, and cyclohexene (4). It is possible therefore that this organometallic is formed in ether also, but to 13 a lesser extent at the lower temperatures. (D) Reaction of methylene iodide with magnesium yielded only an unusually unreactive, crystalline Grignard reagent of the structure

CH2 (Mgl)2 (10), which evolves methane upon hydrolysis.

(10)(a) G. Emschwlller, Compt. rend., 183. 665 (1926); (b) D. Y. Chang and Chao-Lun Tseng, Trans. Sci. Soc. China, (1932); (c) D. A. Fidler, J. R. Jones, S. L. Clark, and H. Stange, J. Am. Chem. Soc., 77. 663 b (1955).

Methylene bromide and zinc-copper couple in ether do not react even when iodine is used as an initiator and the stirred reaction mixture is refluxed for long periods; the couple retains its initial slate-gray color and no gas is evolved when small aliquots of the reaction mixture are hydrolyzed. However, methylenedimagnesium diiodide has recently been prepared in 73$ yield by refluxing methylene iodide and magnesium in ether; methylenedimagnesium di bromide was prepared in 58$ yield by the same procedure

(10c). The experimental conditions described in the magnesium-— methylene bromide reaction were duplicated in the attempted preparation of an organzinc derivative from methylene bromide. Therefore, the decreased reactivity of the zinc-copper couple must be sufficient to prevent reaction.

Reaction of methylene iodide, zinc-copper couple and acetylenes failed. Although the reaction of methylene 14 iodide with zinc-copper in ether was initiated previous to the addition of solutions of either diphenylacetylene or 2 -pentyne in ether, no addition of methylene to either acetylene was detected. The failure of the methylene iodide— zinc-copper reagent to react with diphenylacetylene is not entirely unexpected since ethyl diazoacetate adds to diphenylacetylene at 140° to form 1,2 -diphenylcyclo- propene carboxylic acid in low yield (ll).

(11)(a) R. Breslow, personal communication; (b) R. Breslow and M. Battiste, Chem. and Ind. (London) 1143 (1958).

A logical extension of these methylene iodide— zinc- copper couple experiments involves the reaction of 1,1-di- haloethanes with zinc-copper couple. Conceivably methyl- cyclopropanes could be formed by reaction with olefins.

Initial experiments indicated^ that reaction of zinc-copper couple and 1,1-diiodoethane was more easily initiated than that with methylene iodide, that the organometallic intermediate was less stable, and that ethylene was formed.

For proper control of the reaction, initiation was first effected with a few drops of a 1,1-diiodoethane— ether solution; after cyclohexene had been added, the remaining diiodide was introduced dropwise. Evolution of ethylene was apparent throughout the reaction. Although two minor products which appear to be derivatives of cyclohexene 15 were formed in small amounts, the major product of the reaction was ethylene. Ethylene could result from the decomposition of an intermediate, similar in structure to that formed from the reaction of methylene iodide with zinc-copper couple:

I “Znl2 -- CH3CHI2 + Zn— *[CH3 - CH - Zn-T] ----> [CH2 -*CH] »CH2 =CH2

An important factor contributing to the instability of the carbene is that it could easily rearrange to ethylene by hydrogen migration (12 ).

(12) Diazoethane at 600-650° yields ethylene (by hydrogen rearrangement) and nitrogen [F. 0. Rice and A. L. Glasebrook, J. Am. Chem. Soc., 56, 7^1 (193^)].

Attempts to react 1,1-dichloroethane with zinc- copper couple failed apparently because of the decreased reactivity of the dlhalide toward the couple. EXPERIMENTAL

General Information

Melting Points. All melting points were determined on a Plsher melting point block and are un corrected.

Bolling Points. Unless noted otherwise, boiling points were determined as the compounds distilled.

Thermometer corrections were not made. Boiling points for which pressures are not recorded were taken at atmos pheric pressure.

Infrared Spectra. The infrared spectra of the compounds prepared in this research were obtained with a

Baird Associates, model B, recording infrared spectropho tometer.

Materials

Zinc. Mallinckrodt zinc dust, reagent grade, was used to prepare the couple.

Ether. Anhydrous ether, Mallinckrodt analytical reagent, was used directly without additional drying or purification.

16 Methylene Iodide. The methylene iodide was ob tained from the National Biochemicals Company and from

Matheson, Coleman, and Bell, and in each case it was stabilized by tin. In several experiments with zinc- copper couple, freshly distilled methylene iodide was used; in most reactions it was used without rectification.

Methylene Bromide. Methylene bromide obtained from the Dow Chemical Company was dried and distilled before use.

1,1-Dichloroethane. 1,1-Dichloroethane from the

Eastern Chemical Corporation was dried and rectified.

Olefins. The olefins used were commercially available compounds which were purified previous to reaction.

Gas Chromatography

Products from reactions of methylene bromide,

1,1-diiodoethane, and 1,1-dichloroethane were analyzed with an Aerograph Gas Chromatograph connected to a 2.5 millivolt full-scale deflection Brown Recorder; the chro matograph was equipped with a hot-wire detector and helium was used as the carrier gas. Products from the reaction of zinc-copper couple and methylene iodide with olefins were examined with a chromatographic unit constructed with a

Gow-Mac detector and a one millivolt full-scale Bristol 18

Dynamaster Recorder. Nitrogen was used as the carrier gas with this apparatus. The columns used in the gas chromato graphic units were prepared by thoroughly coating 30-60 mesh fire brick (13) with an ether solution of the substrate

(13) Purchased from the Wilkins Instrument and Research Corporation, Walnut Creek, California.

(polyethylene glycol 400 or Triton X-100); then after the solvent had been removed, the coated material was packed with the aid of a vibrator into 1/4 Inch outside diameter glass or stainless steel tubing of appropriate length. For the analysis of mixtures, the flow rate of the carrier gas was regulated so that efficient separation was effected.

Peak areas were used to determine product composition (14). It is believed that no great error is

(14) A recent Investigation reveals that determi nation of percentage composition of hydrocarbons from peak areas is accurate [E. M. Fredericks and F. R. Brooks, Anal. Chem., 28, 297 (1956)]. introduced if corrections are not made for differences In the thermal conductivities of the compounds involved (15).

(15) Studies of a representative mixture contain ing aromatic, cyclic, and aliphatic hydrocarbons, acetone acetaldehyde, and methyl and ethyl alcohols Indicate that the maximum error resulting from the assumption that all the compounds possess the same thermal conductivities is 3.5 per cent [M. Dimbat, P. E. Porter, and F. H. Stross, Anal. Chem., 28, 290 (1956)3. 19

Intermediates

Zinc-Copper Couple

Zinc-powder (32.8 g., 0.5 mol.) was washed suc cessively with hydrochloric acid (3$, 5 x 25 ml.), distilled water (4 x 30 ml.), aqueous copper sulfate

(2 $, 2 x 50 ml.), distilled water (4 x 30 ml.), absolute ethanol (4 x 30 ml.), and absolute ether (2 x 25 ml.) (16).

(16) (a) The washings were performed conveniently by stirring a mixture of the zinc powder and each wash solution with a porcelain spatula in an open beaker and then decanting the supernatant liquid; (b) The washings with hydrochloric acid should be done rapidly to avoid adsorption of bubbles of hydrogen on the zinc which makes subsequent washings more difficult; (c) The absolute ethanol and absolute ether washings were decanted di rectly on a Bflchner funnel to prevent loss of the couple.

The couple was finally transferred to a Btfchner funnel, washed with additional ether, covered tightly with a rubber dam, and suction dried until it reached room temperature.

The zinc-copper couple can then be used immediately or stored for future reactions.

1 ,1-Diiodoethane

A mixture of ethylidene chloride (33.0 g., 0.33 mol.), ethyl iodide [156 g., 1.0 mol.](17) and a

(17) When methyl iodide was used instead of ethyl Iodide, a slightly reduced yield of 1,1-diiodoethane was obtained. 20

catalytic amount of aluminum chloride (1.5 g.) was stirred

magnetically and heated (60-80°) for 5 1/2 hr. (18).

(18) R. L. Letsinger and C. W. Kammeyer, J. Am. Chem. Soc., Jft, 4476 (1951).

During this period of heating the ethyl chloride (b.p. 13°)

formed in the equilibration reaction was removed. After the

reaction mixture had been cooled, it was poured into cold

water, washed successively with aqueous potassium bicarbo

nate and sodium bisulfite solutions, and finally with ice

cold water. The dense, dark organic layer was then dried

over magnesium sulfate and fractionated through a glass

helix-packed column (1.4 by 23 cm.). 1,1-Diiodoethane

(32.2 g., 0.114 mol.), b.p. 72-73°/23 mm., lit. (18) b.p.

75-76°/25 mm., was isolated (19).

(19) 1,1-Diiodoethane becomes colored even when stored over a tin stabilizer at 0°.

Reactions of Methylene Iodide. Zinc-Copper Couple, and Olefins

General Procedure

The general technique used for the synthesis of cyclopropanes from olefins is summarized. Any modification in this procedure is described in detail in each individual synthesis. 21

Methylene Iodide (20) and iodine were added to a

(20) Regardless of whether the methylene iodide was freshly distilled or whether the original straw-colored liquid was used in the reaction, no difficulty was en countered in the preparative procedure and the same results were obtained. suspension of zinc-copper couple in anhydrous ether con tained in a flask equipped with a stirrer and an efficient water condenser fitted with a calcium chloride tube. After the iodine color had disappeared, the initial gray-colored mixture was refluxed for 30 minutes (21). During this

(21) The minimum time for effecting initiation has not been determined. period the mixture darkened, and this color change was ac companied by a gentle exothermic reaction. External heating was discontinued and the olefinic compound in anhydrous ether was added dropwise in 30 minutes. During addition the mixture continued to reflux. Heating was resumed and the mixture was refluxed for the specified length of time

(22). The reaction mixture was cooled and filtered

(22)(a) The reaction appears essentially complete after 4-6 hr. of refluxing. At this time the mixture is dark red-brown and precipitation of white zinc iodide is apparent; (b) The presence of active reagent from methylene iodide and zinc-copper can be determined conveniently by adding an ali quot to water and noting the volume of gases produced; (c) There were no differences apparent when these reactions were conducted under nitrogen or in the presence of air. through a Super Cel pad on a Bttchner funnel. The residue was washed thoroughly with ether and this ether solution was washed successively with hydrochloric acid, aqueous

sodium bicarbonate, and saturated aqueous sodium chloride.

The water layers were washed with ether and then the ether

extracts were combined and filtered through anhydrous mag nesium sulfate. After the ether had been removed through

a packed column, a mixture of the starting olefin and the

corresponding cyclopropane remained. This mixture was

subsequently analyzed by distillation and/or gas chromato

graphic techniques.

B1eyelo[4.1.0]heptane from Cyclohexene

Experiment I. A mixture of methylene iodide (40.2

g., 0.15 mol.), a crystal of Iodine, zinc-copper couple

(14.4 g. of zinc, 0.22 mol.), and cyclohexene (24.6 g.,

0.30 mol.) In ether (75 ml.) was refluxed for 67 hr. be

fore being worked up according to the General Procedure.

After the ether had been removed and the residue had been distilled through a glass helix-packed column (1.4 by 24 cm.), bicyclo[4.1 .0 ]heptane, b.p. 116°, nD25 1.4542, nD20 1.4566, lit. (4b) b.p. 116.5°, nD2$ 1.4546, was ob tained in _ca. 50$ yield. Analysis by gas phase 23 chromatography (23 ) also revealed that bicyclo[4.1.0]hep-

(23 ) A k0% polyethylene glycol 400 column (8 ft.) at 68° with nitrogen carrier gas (27.5 cm.) was used for the analysis. tane was formed in 50$ yield.

Experiment II. A mixture of methylene iodide

(53.6 g., 0.2 mol.), a crystal of iodine, zinc-copper couple (19.7 g. of zinc, 0.3 mol.), and cyclohexene

(32.8 g., 0.4 mol.), in ether (100 ml.) was refluxed for

64 hr. before being worked up. After the ether had been removed a mixture (31*7 g) of cyclohexene and bicyclo[4.1.0]- heptane remained (24). Analysis of this mixture by gas

(24) The infrared spectra of the mixture indi cated the presence of an olefin band at 6.08 p and a cyclopropane band at 9.88 jjl. Methylene iodide was not detected. phase chromatography (23 ) indicated that bicyclo[4.1 .0 ]- heptane was formed in 47^ yield. n-Hexvlcvclopropane from 1-Octene

Experiment X* A mixture of methylene iodide

(53.6 g., 0.20 mol.), a crystal of iodine, zinc-copper couple (19.8 g. of zinc, 0.30 mol.), and 1-octene (44.8 g.,

0.40 mol.) in ether (90 ml.) was refluxed 19 hr. After the ether had been removed through a packed column, a mixture

(46.2 g.) of 1-octene and n-hexylcyclopropane remained. 24

Analysis by gas phase chromatography (23) revealed that n-hexylcyclopropane was obtained in 55$ yield. Rectifi cation of an aliquot of the reaction mixture in a Nester spinning band column allowed separation of n-hexylcyclo propane in ca. 50$ yield, b.p. 148-150°, nD25 1.4173, lit. (4b) b.p. 148°, nD25 1.4160. The infrared spectra of n-hexylcyclopropane showed absorption for a cyclo propane ring at 9.88 jj. but no absorption for an olefin at 6.08 ^i.

Experiment II. The amounts of reagents and re action conditions were identical to Experiment I except total reflux time was increased to 67 hr. A mixture

(46.7 g.) of 1-octene and n-hexylcyclopropane remained after removal of the ether (25). Gas chromatographic

(25) The infrared spectra1of the crude mixture indicated that methylene iodide was not present. analysis (23 ) indicated the formation of n-hexylcyclopropane

In 50$ yield.

Experiment III. The reaction conditions and amounts

of reagents were identical to that of Experiment I except

reflux time was 41 hr. and a large excess of zinc-copper

couple (32.7 g. of zinc, 0.5 mol.) was used. When the

crude reaction mixture was first washed with 5$ hydrochloric acid, a large amount of gas (probably methane) was evolved. 25

After the ether had been removed a mixture (45.9 g.) of

1-octene and n-hexylcyclopropane was isolated. Tt was concluded, after analysis of this mixture by gas phase chromatography (23 ), that a 38$ yield of n-hexylcyclo propane was obtained.

Experiment IV. A mixture of excess methylene iodide (67.0 g., 0.25 mol.), a crystal of iodine, zinc- copper couple (13.6 g. of zinc, 0.20 mol.) and 1-octene

(44.8 g., 0.40 mol.) in ether (175 ml.) was refluxed 48 hr. After the ether had been removed analysis of the A crude product (47.2 g.) by gas phase chromatography (23 ) indicated that n-hexylcyclopropane was obtained in 47$ yield.

Experiment V. Methylene iodide (53.6 g., 0.20 mol.), zinc-copper couple (16.3 g. of zinc, 0.25 mol.), and 1-octene (44.8 g., 0.4 mol.) were reacted in anhydrous ether (125 ml.) according to the General Procedure. The total reflux time was 30 hr. After the ether had been removed through a packed column a mixture (47.7 g.) of

1-octene and n-hexylcyclopropane was Isolated (25).

Analysis by gas chromatographic techniques (23 ) indicated that n-hexylcyclopropane was formed In 48$ yield. 26

1-Methyl-4-(1-methylcvclopropyl)- eyelohexene from f+)-Llmonene

A mixture of methylene iodide (80.4 g., 0.30 mol.)*

(+)-limonene (20.4 g., 0.15 mol.), and zinc-copper couple

(21.8 g. of zinc, O .33 mol.) in ether (140 ml.) was re fluxed for 70 hr. and treated in the usual manner. A crude mixture (25.3 g.) of (+)-llmonene and l-methyl-4-(l-methylcyclopropyl)eyelohexene remained after removal of the ether.

Distillation of an aliquot (10.72 g.) of this mixture through a Nester spinning band column gave (+)-limonene

(2.68 g.) and l-methyl-4-(l-methylcyclopropyl)cyclohexene

(4.88 g., 51# yield based on total weight of crude product), b.p. 69.5-70.2°/8 mm., nD25 1.4687, lit. (4b) b.p. 73°/8.5 mm., nD25 1.4679.

2 -0xablcyclo[4.1 .0 ]heptane from Dlhydropyran

Methylene iodide (67.0 g., 0.25 mol.), zinc-copper couple (21.8 g. of zinc, O .33 mol.), dlhydropyran (12.6 g.,

0.15 mol.), a crystal of iodine, and ether (150 ml.) were combined according to the General Procedure and refluxed for 20 hr. After the reaction mixture had been cooled, it was filtered through a Super Cel pad and the residue was washed with additional ether. The filtrate was washed thoroughly with cold ammonium hydroxide and then with ice water until the aqueous washings were neutral to litmus.

After the aqueous washings had been extracted once with ether, the ether layers were combined, washed with cold saturated aqueous sodium chloride, and filtered through anhydrous magnesium sulfate. The ether was removed through a glass helix-packed column; a crude mixture (16.2 g.) of dlhydropyran and 2-oxabicyclo[4.1.0]heptane remained (25).

Analysis by vapor phase chromatography (23 ) revealed that

2-oxabicyclo[4.1.0]heptane was formed in 66# yield.

Unsuccessful Reactions of 1.1-Dlhalldes. Zinc-Copper Couple, and Unsaturated Compounds

Methylene Iodide. Zinc-Copper Couple. and Dlphenylacetylene -

Reaction was initiated as described in the General

Procedure with zinc-copper couple (16.3 g. of zinc, 0.25 mol.), methylene iodide (46.9 g.j 0.175 mol.) and iodine

(0.2 g.) in anhydrous ether (100 ml.). External heating was stopped and dlphenylacetylene [17.8 g., 0.10 mol.] (26)

(26) Dlphenylacetylene (m.p. 60-61°) was prepared according to "Organic Syntheses. Vol. 34, John Wiley and Sons, Inc., New York, 1954, p. 42.

in anhydrous ether (50 ml.) was added dropwlse in 50 min.

Heating was resumed and the mixture was refluxed for 46 hr.

The reaction mixture was cooled and treated in the usual 28 manner. After the ether had been removed a pale yellow liquid (18.6 g.) remained which solidified upon cooling

(m.p. 35-50°). The infrared spectra of this solid, both before and after recrystallization from grain alcohol, was identical to that of dlphenylacetylene. The recrystal lized material, m.p. 59.0-60.0°, did not depress the melt ing point of authentic dlphenylacetylene.

Methylene Iodide. Zinc-Copper Couple. and 2 -Pentyne

Methylene iodide (53.6 g., 0.20 mol.) and a crystal of iodine were added to a suspension of zinc-copper couple

(19.6 g. of zinc, 0.30 mol.) in ether (100 ml.). After the characteristic reaction had been initiated, a solution of 2 -pentyne [20.4 g., 0.30 mol.] (27) in ether (25 ml.)

(27) Analysis of 2-pentyne by gas phase chromato graphy on a 35$ polyethylene glycol 400 column (5 ft.) at 24 , pressure 30.4 cm. helium, failed to show any impuri ties. was added dropwise in 20 min. After the dark reaction mixture had been gently refluxed for 31 hr., it was treated in the typical manner previously described. Upon analysis by gas chromatography the dried, crude reaction mixture showed the presence of only ether and 2 -pentyne (27). 29

Methylene Bromide and Zinc-Copper Couple

Methylene bromide (34.8 g., 0.20 mol.), zinc-copper couple (16T3 g» of zinc, 0.25 mol.), several small crystals of iodine, and ether (125 ml.) were stirred under reflux for

46 hr. Since the reaction mixture retained Its initial slate-gray color and no gas was evolved when small aliquots of the mixture were placed in water, it was concluded re action had not been initiated; therefore no olefin was added, and the experiment was discontinued.

1.1-Dichloroethane. Zinc-Copper Couple, and Cyclohexene

Several milliliters of a solution of 1,1-dichloro ethane (15.0 g., 0.15 mol.) in ether (20 ml.) was dropped into a stirred suspension of zinc-copper couple (16.4 g. of zinc, 0.25 mol.) in ether (100 ml.). This mixture was refluxed one hour before cyclohexene (27.4 g., O .33 mol.) was added; the remainder of the dichloroethane— ether so lution was then added dropwise in 3 hr. Although the stirred reaction mixture appeared unchanged after being refluxed for 43 hr., it was worked up and dried in the usual manner. Wien this mixture was fractionated through a glass helix-packed column, the only compounds found were ether, 1,1-dichloroethane, and cyclohexene. 30

1.1-Dllodoethane. Zinc-Copper Couple. and- Cyclohexene

To a magnetically stirred suspension of zinc-copper couple (7.8 g., 0.12 mol.) in ether (100 ml.) was added a few drops of a solution of 1,1-diiodoethane (22.5 g.* 0.08 mol.) In anhydrous ether (50 ml.). Within 20 mln. the mixture darkened and the reaction appeared initiated.

Cyclohexene (21.0 g., 0.25 mol.) was added and the dropwise addition of the 1,1-diiodoethane— ether solution was resumed. This addition was completed in 2 hr. (28); then

(28 ) In a preliminary experiment in which all the 1.1-diiodoethane was added rapidly, a vigorous reaction ensued with the spontaneous elimination of gas analyzed by G. P. C. to be ethylene. the reaction mixture was stirred at room temperature for

10 hr. and at reflux for 5 hr. During this time ethylene was slowly evolved. After the usual workup and the removal of ether and most of the cyclohexene, a light yellow liquid (3.4-6 g.) remained. Analysis by gas phase chromato graphy (29) indicated the liquid was cja. 50$ cyclohexene;

(29) A 35$ Triton X-100 column (5 ft.) at 88° with helium carrier gas (37.1 cm.) was used for the analysis. the remainder consisted of two unidentified compounds present in a 2:1 ratio. PART IT

REACTIONS OF METALS AND GEM-DIHALIDES

31 INTRODUCTION

Carbenes (l) have been a subject of renewed interest

(l) Confusion and ambiguity exists in the liter ature in the nomenclature of gem-divalent radicals. The term "carbene" will be used in this study to denote this family of divalent radicals in general. The first member of this homologous series will be named methylene (H2 C:); all other gem-divalent radicals will be named by adding "-idene" to the name of the corresponding univalent radical [International Union of Pure and Applied Chemistry Report on Nomenclature, J. Am. Chem. Soc., 82, 55^5 (i960)]. Several examples are shown below;

ch3 cyclopropylidene sec.-butyl idene neopentylidene in the past decade. New syntheses of divalent carbon inter mediates have been devised and evidence for the presence of carbenes in numerous reactions has been found. For example, carbenes are possible intermediates in decomposition -of diazo compounds (2 ) in aprotic solvents, and in

(2)(a) L. Friedman and H. Shechter, J. Am. Chem. Soc. 81, 5512 (1959); (b) Ibid.. 82. 1002 (i960); (c) L. Friedman, Ph.D. Dissertation, The Ohio State University, (1959); (d) J. W. Powell and M. C. Whiting, Tetrahedron, J, 305 (1959); (e) L. Friedman and H. Shechter, personal communication, (f) Report of Professor A. C. Cope,

32 33

Massachusetts Institute of Technology, Cambridge, Mass. at Welch Foundation Lectures, Houston, Texas, November, I960

(X-elimination reactions of alkyl halides (3) and methylene

(3) (a) W. Kirmse, Angew. Chem., 72, 716 (i960); (b) L. Friedman and J. G. Berger, J. Am. Chem. Soc., 82. 492, 500 (1961); (c) J. G. Berger, M. Sc. Thesis, New York University, (i960); (d) W. Kirmse and W. von E. Doering, Tetrahedron, ljL, 266 (i960); (e) P. S. Skell and A. P. Krapcho, J. Am. Chem. Soc., 83. 754 (1961). and ethylidene dichlorides (3a,c)(4) with strong bases.

(4)(a) G. L. Closs and L. E. Closs, J. Am. Chem. Soc., 81, 4996 (1959); (b) G. L. Closs, Abstracts of 138th Meeting of the American Chemical Society, New York, N. Y., Sept., I960, p. 9-P; (c) G. L. Closs in Chem. and Eng. News, 38, No. 38, 54 (I960); (d) G. L. Closs and L. E. Closs, J. Am. Chem. Soc., 82, 5723 (i960).

These intermediates form olefins by migration of hydrogen on neighboring carbons (^-hydrogen), cyclopropanes by intramolecular insertion into a V-carbon-hydrogen bond, carbon-skeleton rearrangement products by migration of alkyl groups, and bicyclic derivatives by transannular hydrogen insertion in medium-sized rings (7-10 carbons).

As an additional study of the properties of carbenic intermediates generated by various methods, investigations of the syntheses of representative 1,1-dihaloalkanes and

1,1-dihalocycloalkanes and their reactions with active metals were undertaken. Conceivably metals such as sodium, magnesium, and zinc-copper couple could remove the two halogen atoms from a gem-dlhalide and generate a carbenic

Intermediate which would undergo various intramolecular processes. Reactions of active metals with the following gem-dlhalides were investigated: 1,1-dibromoethane, 1,1- dibromopropane, 1,1-dibromobutane, 1,1-dichloropropane,

1,1-dichlorobutane, 1,l-dichloro-2 ,2 -dimethylpropane

(1,1-dichloroneopentane), 1,1-dichlorocyclobutane, 1,1- dichlorocyclopentane, 1,1-dichlorocyclohexane, and 1,1- dichlorocyclooctane. Reactions involving 1,1-dichloro cyclobutane and 1,1-dichlorocyclooctane have particular interest since cyclobutylidene and cyclooctylidene as generated from the corresponding diazo compounds undergo extensive carbon-skeleton rearrangement and transannular insertion respectively (2b,c,e,f). Since 1,1-dimethylcyclopropane formed by intramolecular carbon-hydrogen insertion is the principle product from neopentylidene

(2 a,c)(3b,c,e)(4b,c), reactions of 1,1-dichloroneopentane with metals may contribute additional information about this intermediate. Results from reactions of other gem- dihalides with metals would furnish additional evidence for the formation and properties of carbenic intermediates. HISTORICAL

The present review is concerned principally with the chemistry of intramolecular reactions involving car benic intermediates or transition states having carbenic character. Intermolecular reactions of carbenic species have been, extensively reviewed elsewhere (5).

(5) (a) W. Kirmse, Angew. Chem., 23.* 161 (1961); (b) Ibid.. 21, 537 (1959); (c) R. Huisgen, ibid., 62, 439 (1955); (d) B. Eistert in "Newer Methods of Preparative Organic Chemistry," Interscience Publishers, Inc., New York, New York, 19^8, P. 513.

Simple diazo alkanes, prepared in situ, decompose carbenically in aprotlc solvents with loss of nitrogen to give cyclopropanes by intramolecular insertion (6) and

(6) The first unequivocal evidence in support of mechanisms involving direct insertion of methylene across carbon-hydrogen bonds was obtained from photolysis of diazomethane in presence of 2-methylpropene-l-C1 . [W. von E. Doering and H. Prinzback, Tetrahedron, 6, 24, (1959)]. olefins by hydrogen migration (2a,c,d). An intensive study of this reaction, including the effect of aprotic and protonic solvents on product distribution, allows the con clusion (2 a,c) that the proton-donating ability of the solvent determines whether the diazo compounds decompose by carbenoid or cationoid processes. The decomposition

35 36 of 2 -methyldiazopropane is indicated as follows:

Protonic solvent;

CH tj+ CH 3 n CHo . CH-CH=N2 H ^ 3vCH-CH2N2 --- ► 3> - CH-CHr -CH CH, CH, 3

CH 3 v „ CH c=ch2 3^ch-ch2+ CH. CH, c h 3n ,h c h 3n CK CHoCHpCH=CH2 + V-C*Cv + ^C=C 3 32 * H CH3 K Ti

Aprotic solvent;

CIV -N2 CH3' ^CH-CH=N? ->CH-HC: ch3 ch3

Thus, in aprotic solvents, decomposition by carbenoid processes gives 2 -methylpropene by hydrogen transfer and methylcyclopropane by intramolecular carbon-hydrogen in sertion, while in protonic solvents cationoid processes resulting in carbon-skeleton and hydrogen rearrangements occur (7).

(7) Results of decomposition of tosylhydrazones in aprotic solvents (2 a,b,c) will be referred to frequently in later sections. 37

Reactions of neopentyl chloride and strong bases give 1,1-dimethylcyclopropane (8)(3b,c,e); similarly,

(8)(a) P. C. Whitmore, A. H. Popkin, and J. R. Pfister, J. Am. Chem. Soc., 61, 1616 (1939); (b) P. C. Whitmore, A. H. Popkin, H. I. Bernstein, and J. P. Wilkins, ibid.. 63, 124 (1941): (c) P. C. Whitmore and H. D. Zook, ibid., M , 1783 (1942). methylcyclopropane and isobutylene are obtained from iso butyl chloride (9)(3a>b,c,d). These reactions were initially

(9) F. E. Condon and D. E. Smith, J. Am. Chem. Soc., £2, 965 (1947). believed to involve free radicals (8) but since then experi mental evidence indicates that dehydrohalogenation of pri mary halides with bases can occur via

OC-Elimination occurs only slightly in conversion of n-octyl bromides to 1-octene with sodamide in liquid ammonia (10). However, recent studies indicate that alkyl

(10)(a) D. G. Hill, W. A. Judge, P. S. Skell, S. W. Kantor, and C. R. Hauser, J. Am. Chem. Soc., 74. 5599 (1952); (b) S. M. Luck, D. G. Hill, A. T. Stewart> Jr., and C. R. Hauser, ibid., 81, 2784 (1959). halides in the presence of strong bases such as phenyl- or butyllithium or sodium undergo (^-elimination to form carbaies which yield cyclopropanes and olefins (3 ); y^-elimination may also take place. For example, 89$ o<-elimination occurs in the reaction of l-chloro-l,l-dideutero-2 -methylpropane and phenylsodium (3b); only 78# « -elimination is observed when

sodium Is used (3a*d).

H B: CH3-CH-CD2 CI ► CHo-C -CDoCl CHqC=CDp ^ I J\ ch3 ch3 CH,

/B D

CH,-CH-C-C1 -> CH3-C-CD 3 1 1 ^ D CH

•CHo + CHp-C=CHD

With primary alkyl chlorides and lithium only^-elimination

is effected (3a*d). y^-Elimination also predominates in reactions of alkyl bromides or sec-alkyl chlorides with

sodium or potassium. A related (X-elimination occurs in reaction of methylene chloride with butyllithium to give chlorocarbene (4a,d):

CH2 Cl2 + n-BuLi --- >» BuH + LiCl + :CHC1. 39

The resulting chlorocarbene Is trapped by olefins (11) to

(11) W. von E. Doerlng and A. K. Hoffmann, J. Am. Chem. Soc., 76. 6162 (195^)* give chlorocyclopropanes. Similarly 1-chloroethylidene is formed from reaction of ethylidene chloride and isopropyllithium (3a)* 1-Chloroethylidene does not rearrange to vinyl chloride.

If chlorocarbenes are generated from gem-dlchlorldes and alkyllithium compounds in the absence of any other nucleophilic substrates, the carbene combines with excess alkyllithium to form a new carbene (3a,c)(4):

Cl „Li-LiCl RLi + R'CHClg — — ►R'-C: + RLi >R'Rc' ~ ^R-C-R NC1

Products resulting from characteristic carbene isomerizations were isolated. From t_-butyllithium and methylene chloride, neopentylidene was formed which gave a mixture of 1,1-dimethylcyclopropane, 2 -methyl-2 -butene, and 2 -methyl-

1-butene (4b,c):

iH 3 f 3 u - ? H 3 CH^-C-Li + :CHC1 ----► CH^C-HC'^ >-CH3-C-HC: + LiCl ch3 ch3 ch3

18* 13* 69* 40

Isopropyllithium and ethylidene chloride react via 3-methyl-

2 -butylldene to give 2 -methyl-2 -butene and 3-methyl-l-butene

in 93 and 7% yields respectively; cyclopropanes were not detected (3a).

Although reactions of gem-dihalldes with metals have not been extensively investigated, evidence does exist

for formation of carbene or carbene-like intermediates in

such systems. Tollens (12) identified hydrogen, acetylene,

(12) B. Tollens, Ann., 137. 311 (1866). ethylene, ethane, and chloroethylene from reaction of

ethylene, ethane, and chloroethylene from reaction of ethylidene chloride and sodium at 180-200°. Later to ex plain the chemiluminescence of reactions of sodium with methylene and ethylidene halides, formation of methylene and ethylidene was postulated (13). While ethylene was the

(13) C. E. H. Bawn and W. J. Dunning, Trans. Fara day Soc., 35, 185 (1939). principle product, there was evidence that hydrocarbons

(ca. 5$) were formed from ethylidene bromide. These higher hydrocarbons were Initially believed to have been derived

from ethylidede. However, it was subsequently concluded

that ethylidene had not been formed as an intermediate since ethane was not obtained when reaction of ethylidene bromide 41

and sodium was effected in the presence of hydrogen (14).

(l4) C. E. H. Bawn and J. Milstead, Trans. Faraday Soc., 889 (1939).

Ethylene is produced from methylene bromide and sodium

vapor; methane is produced in the presence of hydrogen (14).

Comparison of results of the reactions of sodium

with methylene and ethylidene dibromides may not be valid

since ethylidene does not have properties similar to those

of methylene; ethylidene possesses a strong driving force

for rearrangement to ethylene:

Diazoethane at 600-650° yields ethylene and nitrogen (15).

Since the Paneth effect with silver mirrors, which is

characteristic in decomposition of diazomethane, is not

shown with diazoethane (l5)j the life of ethylidene, if it

(15) P. 0. Rice and A. L. Glasebrook, J. Am. Chem. Soc., J26, 741 (1934).

is formed, must be exceedingly short. Union of methylene

radicals to form ethylene apparently does not occur with as

high an efficiency or with as low of an activation energy

as the intramolecular hydrogen rearrangement of the ethyli

dene radical to form ethylene. More recent investigation

leads to the picture that the intermediates from reactions 42 of sodium with organic polyhalides are chemisorbed on the excess sodium (16). High yields of ethylene were obtained — - - - - - — - ■

(16) A. Saffer and T. W. Davis, J. Am. Chem. Soc., 61, 641 (1945). from the reactions of both methylene and ethylidene chlorides with sodium.

An elegant synthesis of cyclopropanes involves re action of methylene iodide and zinc-copper couple with ole- finp (17). The mechanism of this reaction may involve

(17)(a) H. E. Simmons and R. D. Smith, J. Am. Chem. Soc., 80, 5323 (1958); (b) ibid.. 81, 4256 (1959); (c) This reaction is discussed in detail •’n Part T of this disser tation. addition of methylene, or more likely a methylene-z'nc

‘ocT'de complex, across carbon-carbon double bonds in a manner similar to that of methylene derived from diazo methane or ketene (18).

(18) (a) W. von E. Doering, L. H. Knox and M.- Jones, Jr., J. Org. Chem., 24, 136 (1959;; (b) W. von E. Doering and P. La Flamme, J. Am. Chem. Soc., J8, 5447 (1956); (c) H. M. Frey, ibid., J3.» ^ 5 9 (1957).

Doering and La Flamme (19) have prepared allenes

(19) W. von E. Doering and P. M. La Flamme, Tetra hedron, 2 , 75 (1958). from 1,1-dibromocyclopropanes and magnesium or sodium. >3 Likewise, allenes result from reactions of 1,l-dichloro-2-

alkylcyclopropanes with magnesium and alkyl or aryl halides (20). A mechanism involving a cyclopropylidene intermediate

(20) T. J. Logan, Tetrahedron Letters, [53* 173 (1961).

has been suggested; alternate mechanisms involving allyl radicals or allyl carbanions are also possible (19):

i I -C. -C -c I I :cx II -C* -C' c - x I I I -c •

1 e i 1 e

ii /# C — X I -X' I

-X' i “ X - I I -c n>C: II - C ^ c I II -c I

The most attractive mechanism involves a one- or two-step electron transfer process with loss of halide to form a cyclopropylidene which rearranges to an allene.

Allenes have also been prepared from reactions of gem-dihalocyclopropanes and alkyllithium compounds (21).

(21)(a) R. Moore and H. R. Ward, J. Org. Chem., £5, 2073 (i960); (b) L. Skattebttl, Tetrahedron Letters, [53, 167 (1961). Although carbene Intermediates may be involved in these re actions, trapping techniques (11 ) to demonstrate their presence have failed.

\/ C -LiX II + Li R c II c /\

However, evidence for existence of a cyclopropylidene in the decomposition of diphenyldiazocyclopropane has been reported (22). The presence of this carbene was detected

(22) W. M. Jones, J. Am. Chem. Soc., 82, 6200 (I960). by conventional trapping techniques with olefins (ll); spiranes were formed.

Carbenic intermediates isomerize by at least 4 different paths: (A) Olefins result from migration of hydrogen from neighboring carbons (^-hydrogen); (B) Cyclo- propanes result from intramolecular insertion into a

^-carbon-hydrogen bond; (c) Carbon-skeleton rearranged products result from alkyl migration; and (D) Bicyclo derivatives result from transannular insertion. Of these processes, the most favored generally is hydrogen migration to form olefins. For example, butylidene rearranges to 1- butene (92-99#) and methylcyclopropane [1-5#] (2a,c)(3b,c). 45

However, if only one /^-hydrogen is available for migration, intramolecular Insertion to yield cyclopropanes becomes significantly favored. Thus, methylcyclopropane is obtained from isobutylidene in c£. 35# yield (2a,c)(3a,b,c,d). If

'•$-hydrogens are not present intramolecular insertion be comes predominant; alkyl migration in aliphatic carbene intermediates also occurs only wheny^-hydrogens are absent.

These effects are exhibited by neopentylidene from which

1,1-dimethylcyclopropane (42-89#) and 2-methyl-2-butene

(3.8-13#) are isolated (2a,c)(3a,b,e)(4b,c). Compounds arising from carbon-skeleton rearrangements however are the principle products from carbenes derived from 3~ and

4-membered rings (2a,c). For instance, cyclopropyldiazo- methane on carbenic decomposition gives cyclobutene (82#) by ring expansion, while diazocyclobutane forms methylenecyclopropane (70-80#) by ring shrinkage and cyclobutene

(10-13#) by hydrogen migration. Small amounts of products resulting from ring opening reactions are also formed.

Transannular insertions of simple cyclocarbenes have recently been found (2e,f). Although such reactions have not been detected in simple 5- and 6-membered rings, they occur extensively in medium-sized rings (7 to 10 car bons). For example thermal decomposition of diazocyclo- octane in diethyl carbitol gives cis-bicvclof3.3.0 3octane

(46#) and bicyclo[5.1.0]octane (9#) by transannular insertion and cls-cyclooctene (45$) by 1,2-rearrangement of hydrogen. Similar bicyclic products are formed from diazocycloheptane, diazocyclononane, and diazocyclodecane. SUMMARY

Results of reactions of active, metals with the following dihalides are reported: 1,1-dibromoethane,

1,1-dichloropropane, 1,1-dibromopropane, 1,1-dichlorobutane, 1,1-dibromobutane, 1,l-dichloro-2,2-dimethylpropane, 1,1-dichlorocyclobutane, 1,1-dichlorocyclopentane, 1,1-dichlorocyclohexane, and 1,1-dichlorocyclooctane.

In general, the reactions of 1,1-dihaloalkanes and sodium or magnesium give cyclopropanes, alkenes, and alkanes. For example, 1,1-dibromopropane and magnesium in diethyl Carbitol at 96° gives cyclopropane (8.4$), propene (81.6$), and propane (10.0$). Reactions of magnesium, zinc-copper couple, or sodium with other 1,1- dihalides having a^-hydrogen follow the same general trends. However, with 1,l-dichloro-2,2-dimethylpropane, a dichloride which possesses no^-hydrogens, and sodium in hexadecane at 148°, 1,1-dimethylcyclopropane (57.0-

71.5$) is the principal product; 2-methyl-2-butene (14.7-

22.8$), arising, from carbon-skeleton rearrangement, and neopentane (5.0-12.8$) are also formed.

47 48

The principal hydrocarbon from 1,1-dichlorocyclobutane and magnesium is methylenecyclopropane (51.6-55.7$)* a ring contraction product; smaller percentages of cyclo butene (3 1 .2 -35.3$)* cyclobutane (8.4-9.0$), and ring cleavage products (2.9-5*2$) such as l,3~hutadiene, ethene, and the n-butenes are also formed.

Reactions of 1,1-dlchlorocyclopentane and 1,1-di chlorocyclohexane with sodium in hexadecane gives cyclopentene (94.8-95*5$) and cyclopentane (4.5-5.2 $) in 57$ yield and cyclohexene (90.7-93.6$) and cyclohexane (6.4-

9.3$) in 69$ yield respectively. Products arising from transannular insertion become important in reaction of

1 , 1-dichlorocyclooctane and sodium. cis-Bicyclo[3.3.0]- octane (17.8$) and bicyclo[5.1.0]octane (2$) in addition to cis-cyclooctene (7 0.2 $) are isolated in 60$ yield.

The types and relative proportions of hydrocarbons formed in reactions of gem-dihalides and metals are in good agreement with those resulting from decomposition of tosylhydrazones in aprotic solvents (2) and with those derived from alkyl chlorides and strong bases (3 ). The products in these reactions have been explained as being formed via carbeni.c intermediates. Present and previous observations therefore support the postulate that carbenic processes are involved in reactions of gem-dlhalides with sodium or mag nesium. Conceivably these metals remove the two halogen atoms from a gem-dlhallde and generate a carbenic inter mediate which then 1 somor' zes as in reactions with tosyl-

hydrazones (2) or alkyl chlorides (3). Cyclopropanes may

be formed by intramolecular insertation into a Jf-carbon-

hydrogen bond, olefins by migration of hydrogen from

neighboring carbons -hydrogen), carbon-skeleton re

arranged products from alkyl migration, and bicyclo deri

vatives from transannular insertion. Typical rearrange ments and insertion reactions of carbenic intermediates

are illustrated with cyclobutylidene and cyclooctylidene:

• y^-Hydrogen Migration

Na +

V • Carbon-Skeleton Rearrangement

\A -Hydrogen J------>• Migration o

Na + Insertion -Carbon-Hydrogen

Transannular Insertion DISCUSSION

Preparation of gem-Dihaljdes

The gem-dihalldes used in reactions with sodium, magnesium, or zinc-copper couple were generally prepared from phosphorus pentahalide and the appropriate aldehyde or ketone. Although sufficient quantities of the desired products were obtained from these reactions, often the principal compounds formed were the 1-haloolefins. The gem-dihalides prepared and their physical constants and yields are listed in Table 2. Crude yields of the di halides ranged from a high of 5 1.6$ for 1,1-dichlorocyclobutane to a low of 9.9$ for 1,1-dichlorocyclooctane.

A satisfactory technique for reaction of a ketone or aldehyde with phosphorus pentachloride involves dropwise addition of the carbonyl compound onto phosphorus pentachloride. To obtain suitable results it is necessary for the mixture to be cooled to ca. -5° and stirred ef ficiently. The initial reaction is usually vigorous and is accompanied by evolution of hydrogen chloride, which with aldehydes causes trimers and polymers to be formed.

After ca_, one quarter to one third of the ketone or

50 TABLE 2

SUMMARY OP YIELDS AND PHYSICAL PROPERTIES OP GEM-DIHALIDES

Per Cent Per Cent

Dihalidea Yielda B.P./Press. nD at °C Purity6

1,l-Dibromopropaneb 25 .0 66.0-66.8°/8o mm. 1.5037 26° 99 1,l-Dibromobutanec 27.3 57-59o/ 19.5-20.5 mm. 1.4988 25° 99 1,1-Dichloropropane 33.4 85”86°/atm 1.4272 23° 99.5 1,1-Dichlorobutane ,38.0 110.5-112,0°/atm 1.4300 27.5 98.5 1,l-Dichloro-2,2-dimethylpropanea -- " 122 -123 °/atm. 1.4358 27° 98 1,1-Dichlorocyclobutane 51.6 73.0-73.5°/2l8.5 mm. 1.4552 27° 98 1,1-Dichlorocyclopentane 22.8 55°/35 mm. 1.4681 27° 93 1,1-Dichlorocyclohexane 18.2 87°/56 mm. 1.4780 25° 87__ h 1,1-Dichlorocyclooctane 9.9 75-76°/5 mm. 1.4968 26°

(a) Unless noted otherwise, dihalides were prepared from PClc and the ap propriate aldehyde or ketone, (b) Obtained from reaction of d(-bromobutyramide and NaOBr. (c) Synthesized from PCloBrg and butyraldehyde. (d) Contained in a mixture of mono-, di-, and trichlorinated neopentanes received from Dr. L. Friedman, (e) Crude yield, (f) Data not available to calculate yield, (g) Calculated from gas chromato graphic data; the possibility of hydrogen halide being eliminated during the analysis was not investigated, (h) decomposed on gas chromatographic column; its infrared spectra exhibited no bands for carbon-carbon unsaturation; the elemental analysis was correct for 1,1-dichlorocyclooctane.

t—1

I 52 aldehyde Is added, the reaction becomes less vigorous. In the isolation of 1,1-dichlorobutane, the crude reaction mixture from butyraldehyde and phosphorus pentachloride was steam distilled. However, an improved procedure for other dichlorides involved usual extraction and distillation techniques. 1,1-Dichloropropane was distilled directly without any previous treatment for removal of phosphorus oxychloride and excess phosphorus pentachloride.

Newman and Wood (2 3 ) have postulated chlorocarbonium

(2 3 ) M. S. Newman and L. L. Wood, Jr., J. Am. Chem. Soc., 81, 4300 (1959).

ions (il) as intermediates in reactions of aldehydes or ketones with phosphorus pentachloride (See equations below).

A related mechanism had been postulated previously to account for the 1,2-dichloro-2-methylpropane, l-chloro-2- methyl-l-propene, and 1,1-dichloro-2-methylpropane formed from isobutyraldehyde and phosphorus pentachloride (24).

(24) P. D. de la Mare and A. Salama, J. Chem. Soc., 3337 (1956).

2 PCI5 ~ * PCI4 + pci6“ 53

o + R, - Cl R-C-CHR'R" + PCl^ + T + R — C — C - R f,+_£L. R — C — C^-R" OPCI4 H OFCl^ H

Cl I _ R I r -c =c :"„ + POClo + HC1 Cl R' I H R' C-C-R t- 1 OPClh H Cl Rt R-C-C-R" + POClo + Cl* \ 5 + H

+ Cl

R — C Cl, C — R"

Formation of chloroolefins may result from collapse of I, possibly by a cyclic mechanism involving a 6-membered transition state, or stepwise via intermediate II. The structure of the hydrocarbon substituents could affect the stability of intermediates I and II and ultimately influence the relative amounts of chloroolefin and gem-dihalide formed. Such structural effects may have been exhibited in the formation of 1,1-dichlorocyclobutane and 1,1-dichlorocyclooctane since they were obtained in yields of 51.6 and 9.9$ respectively. A cyclobutane ring resists formation of an internal double bond because of ring-strain; in an 8-membered ring, introduction of an internal double bond is relatively favored.

Possibly 1-chloroolefins are formed also by elimi nation of hydrogen chloride from gem-dihalides during work up and distillation of crude reaction mixtures. During analysis of 1,1-dichlorocyclooctane by gas phase chroma tography nearly an equivalent of hydrogen chloride was eliminated with the resulting formation of 1-chlorocyclooctene. Although this type of elimination could have oc curred to a limited extent in the analyses of other gem- dihalides, the matter was not investigated.

1,1-Dibromobutane was synthesized by reaction of butyraldehyde and phosphorus trichloridedibromide. Phos phorus trichloridedibromide, prepared by addition of bromine to phosphorus trichloride at 0 to -5°, reacts with ketones or aldehydes to form gem-dibromides in a manner analogous to that of phosphorus pentabromide. The reaction technique was similar to that used for preparing 55 gem-dichiorides from phosphorus pentachloride

(25).

(2 5) Preparation of 1,l-dihalo-2-methylpropane failed. Reactions of isobutyraldehyde with phosphorus pentahalides resulted in formation of com plex mixtures of halogenated hydrocarbons from which l,l-dichloro-2 -methylpropane could not be isolated. Attempted Hofmann degradation reactions on OC-bromo- isovaleramide (26) were likewise unsuccessful; the un reacted amide was recovered. Hunsdiecker degradation reactions with the silver salt of oi-bromoisovaleric acid produced only a small amount of an unidentified oil. [Consult J. C. Conly, J. Am. Chem. Soc., JS, 1148 (1953) for the techniques used to prepare dihalides via the Hunsdiecker degradation reaction.]

1,1-Dibromopropane was prepared in 25^ yield by

Hofmann degradation of of-bromobutyramide. This pro cedure for preparation of gem-dihalides involves re action of (X.-haloamides with an aqueous solution of bro mine and sodium hydroxide (26). Although this synthesis

(26) C. S. Stevens, T. K. Mukherjei, and V. J. Traynelis, J. Am. Chem. Soc., 78, 2264 (1956). requires the preparation and isolation of both OC-halo acid halides and 0(-haloamides, it does allow separation of the desired dihalide fairly free of contaminants.

l,l-Dichloro-2,2-dimethylpropane was separated from a mixture of mono-, di-, and trichlorinated neopentanes (2 7 ) by rectification (oja. 90% pure),

(27)(a) The mixture was obtained from Dr. L. Friedman; (b) For the chlorination of neopentane 56 consult J. G. Berger, M. Sc. Thesis, New York University (I960). low-temperature fractional crystallization techniques and distillation. Although gas chromatographic analysis indi cated only 2% impurity, additional contaminants could have been present if they and 1,l-dichloro-2 ,2 -dimethylpropane possessed identical retention times (28 ).

(28) Hydrocarbons formed in reactions of 1,1- dichloroneopentane and metals suggest the presence of an undetected impurity in the dichloride.

Reactions of gem-Dlhalides and Metals

The reaction of 1,1-dibromoethane and sodium has been reported to give ethylene, and possibly higher hydro carbons (13) (1-M-) • Since these investigations were con cluded before the advent of gas phase chromatography as a superior analytical tool, reactions were effected to determine the products formed from 1,1-dibromoethane and metals.

The products from reactions of 1,1-dibromoethane with sodium or magnesium are listed in Table 3. Al though ethylene is the principal product in both re actions (57.1 to 95.8$)> a greater proportion of C4 TABLE 3

SUMMARY OP REACTIONS OF 1,1-DIBROMOETHANE WITH METALS

Metal (°C) M g (105) M g (120) Na(ll5)

Solvent13 DECDECHED

Per Cent Yield of Hydrocarbons0 46 75 73

Ethene 78.4d 57. le 95.8d Ethane 9 9.4e ? Methylcyclopropane 1.8 3.4 0.8 Butane 3.0 2.4 0.9 Propene 0.1 0.2 0.1 1-Butene 3.2 6.3 1.8 cis-2-Butene 5.6 11.2 0.2 trans-2-Butene 7.3 10.9 0.5 Acetylene 0.6 0.5 tr.

(a) Abstracted from detailed tables In the Experimental Section, (b) DEC-Diethyl Carbitolj HED-Hexadecane. (c) Calculated yields are based on the volumes of Co gases evolved, (d) Contains an undetermined amount of ethane, (e) Ethylene-ethane distri bution was calculated from analysis on different column.

v_n -J 58 hydrocarbons was obtained with magnesium (20.9 to 34.2$) than with sodium (4.2$).

CH3-CHBr2 — CH2 =CH2

H CHo OH, CHo \ / \ / CHo-CHBro — C=C + C=C 3 . / \ / \ CH3 H H H

Perhaps the 1-butene detected arises" from partial isomeri-_ -

zation of the 2-butenes in the presence of active metals.

Although the formation of methylcyclopropane from ethyli

dene bromide and sodium or magnesium is interesting, there

is insufficient experimental evidence available to postu

late a mechanism. Mechanisms for the reactions of gem-

dihalides and metals will be discussed in greater detail

later in this thesis.

In the present study (Table 4) it has been found

that 1,1-dichloro- and 1,1-dibromoprppanes react with

sodium in decalin or magnesium in diethyl Carbitol to give mixtures of cyclopropane, propene, and propane. The hydrocarbons formed were Identified by gas chromatographic techniques. Their retention times (Dowtherm A I Column) . were identical to those of authentic samples of TABLE 4

SUMMARY OP REACTIONS OP 1,1-DIHALOPROPANES WITH METALSa

1,1-Dichloropropane0 1, 1-D ibromopropane0

Metal (°C) Na(125°) N a (78°) M g (158°) M g (96°)

Per Cent Yield of Hydrocarbons'3 66 56 42 43

Cyclopropane 2.4 2 .0 5.0 8.4 Propene 95.9 97.1 8 8 .1 8 1 .6 Propane 1.7 1 0.9 6.3 1 0 .0

(a) Abstracted from detailed tables in the Experimental Section, (b) Calculated yields are based on the volumes of C3 gases evolved, (c) Solvents: Decalin with Na and diethyl Carbitol with Mg.

U1 vo 60 cyclopropane, propene, and propane. Ethylene is also formed in small yield in reaction of 1,1-dichloropropane and magnesium (2 9).

(29) The ethylene could be derived from the sol vent since it has been reported that strong bases cleave diethyl Carbitol to form C2 hydrocarbons (3c).

Reactions of 1,1-dihalopropanes (as well as the dihalides used in subsequent experiments) and sodium occur instantaneously. However, induction periods of 1 1/2 to

2 1/2 hr. were observed in reactions involving magnesium despite the fact that iodine was used as an initiator.

Table 4 Indicates that the products from reactions of 1,1- dichloropropane with sodium were essentially independent of temperature since their percentage formation remained nearly constant from 78-125°. Reactions of both 1,1-di chloropropane and 1,1-dibromopropane with magnesium gave more cyclopropane, 5.0 and 8.4$ respectively, than did

1,1-dichloropropane with sodium, 2.0-2.4$. Consider ably more propane was formed in the reactions of dihalopropanes with magnesium in diethyl Carbitol (6.3-10.0$) than with sodium in decalin (0.9-1.7$).

A mechanism for formation of the products from the reaction of gem-dihalooropanes (as well as other gem- dihalides in subsequent experiments) with sodium and mag nesium warrants discussion. Although reactions of 61 gem-dihalides and active metals had not been studied

intensively previously, evidence does exist which is compatible with the formation of carbenic intermediates.

The process by which allenes are synthesized from alkyl substituted gem-dlhalocyclopropanes and active metals can be explained by decomposition of transitory cyclopropyl-

idenes (19)(20)(21). Other evidence arises from reactions of methylene and ethylidene halides with sodium (13 )(l^)

(16). to give ethylene. Additional support for the for mation of intermediates having carbenic character is ob tained from isolation of cyclopropanes from reactions of methylene iodide, zinc-copper couple, and olefins (17)(30).

(30) Consult Part T of this dissertation.

Carbenic processes occur also in reactions of (A) tosylhydrazones and bases in aprotic solvents (2 ), (B) in reactions of alkyl halides and strong bases (3 ), end (C) in reactions of alkyllithium compounds and gem-dichlorides

(3a,c)(4). These reactions give cyclopropanes by intra molecular insertion and olefins by rearrangement of car benic intermediates. Reactions of strong bases with deuterated alkyl halides (3a*b,d,e) reveal that ©(-elimi nation to form carbenes occurs to a much greater extent than does the more well-known ^-elimination. 62

The present and previous observations support the postulate that carbenic processes are involved in reactions of 1,1-dihalopropanes with sodium or magnesium.

The reaction can be pictured as shown:

CH0CH«H(£ + MX

-MCI

-2M : CH-CH,

Insertion H Migration

There is no experimental evidence to indicate whether the postulated carbene is formed in a one or 2- step process, or whether the carbene is loosely complexed with the metal or the metal halide. Although the total yield of gaseous hydrocarbons was less in reactions of gem-dihalopropanes with active metals (42-66$ of theory) than in decomposition of propanal tosylhydrazone [70-90$]

(2c), the relative amounts of cyclopropane, propene, and propane formed in each case were similar. This fact lends credence to the existence of propylidene as an intermediate common to both series of reactions.

Formation of propane in the reaction of gem-dihalides with sodium or magnesium must involve reduction. It is conceivable that a series of meta1-hydrogen interchanges could be culminated by disproportionation to give an alkane and an alkene.

M ch3 ch2 chx2 — ch3ch2 hcCx

CH3CH2C -CH3CH2CH2X +CH3CHMCHX2 [CH3CH2CM3^]

M ch3ch2 ch2x -11-->»CH3CH2 CH2 M

CH3CH2 CH2M + CH3CH2 CH2X CH3CH2 CH3 + CH3CH=CH2

It is also possible that ethylidene or ethylidene — metal complex can abstract hydrogen from the dihalide or solvent.

CH3C.H2 CH:

Solvent c h 3c h 2c h 3 c h 3c h 2c h x 2

ch 3ohs ohc” 64

It is interesting that the reactions of 1,1-dibromo- and

1,1-dichloropropanes with magnesium in diethyl Carbitol gave 6.3 to 10$ propane while reactions with sodium in decalin formed only 0.9 to 1.7$ propane. Perhaps the proportion of propane obtained is related to the ease with which hydrogen may be abstracted from the solvents.

A series of reactions involving other gem-dlhalo- alkanes and gem-dihalocycloalkanes was studied to de termine the effects of structure on the types of products formed and to obtain additional evidence to support the postulated existence of carbenic intermediates.

Reactions of 1,1-dichlorobutane and 1,1-dibromobutane with metals followed the same general trends as those for the dihalopropanes. Mixtures of methylcyclopropane, 1- and 2-butenes, and butane were detected (Table

5). Products in which carbon-skeleton rearrangement occurred were not observed. The products obtained and their yields were similar to those from butanal tosylhydrazone and sodium methoxide (2a,c) and to those from butyl halides and strong bases (3b,c). 1-Butene and cls- and trans-2-butenes were isolated from all reactions in volving sodium, but the only olefin formed in reactions with magnesium or zinc-copper couple was 1-butene. It is believed, however, that the only olefin resulting from rearrangement of butylidene is 1-butene, but that in the - TABLE 5

SUMMARY OF REACTIONS OF 1,1-DIHALOBUTANES WITH METALS

1,1-•Dichlorobutane^ 1 ,1 -Dibromobutane^

Metal(°C) Na(ll8) Na(67) M g (175) M g (98) Zn-Cu(100 ) Zn-Cu(75)

Per Cent Yield of Hydrocarbons'3 66e 25f 382 , h 40 62.5° 36

1-Butene 8 7 .0 73.6 84 7 3 .7 8 9 .1 67.2 trans-2-Butene 2.4 10.2 ------9 Me thy1eye1opropane 3.9 • 6 10.7 1.9 1.8 cis-2-Butene 4.0 14.9 --- — --- — Butane 3.7 1.2 10 15.6 8 .9 31.0

(a) Abstracted from detailed tables in the Experimental Section, (b) Calculated yields are based on the volumes of C^ gases evolved, (c) Average of two experiments. (d) Solvents used; diethyl Carbitol wfth Mg and the Zn-Cu reaction at 100°; decalin in all reactions with Na; dimethylformamide with Zn-Cu at 75°. (e) Composition of gases in collector tube, (f) Composition of gases in reaction vessel immediately after reaction, (g) Hydrocarbon mixture contains ca. one per cent ethylene, (h) Percentage composition is average of analysis on 3 different columns.

CTv VJl presence of sodium at elevated temperatures it is lso- merized to els- and trans-2-butenes. This isomerization is supported by the fact that the compos!tion of gases collected remained constant while that in contact with sodium changed even at room temperature (Consult Table 13 in Experimental Section.). Periodic analyses of the gases in the reaction vessel by vapor phase chromatography re vealed that the percentage of 1-butene decreased from

7 3.6$ immediately after reaction to 2 6.9$ eighty-four hours later; the composition of-the els- and trans-2 - butenes present changed from 14.9 to 43.4$ and from 10.2 to 28.8$ respectively. These results are in accord with the findings (3 1 ) that butenes isomerize reversibly in

(31)(a) H. Pines, J. A. Vesely, and V. N. Ipatieff, J. Am. Chem. Soc., XL» 347 (1955); (t) H. Pines and W. 0. Haag, J. Org. Chem., 2^, 328 (1958); (c) ¥. 0. Haag and H. Pines, J. Am. Chem. Soc., 82, 387 (i960). the presence of sodium dispersions or sodium on alumina.

The isomerization of 1-butene is kinetically controlled and yields ci.s-2 -butene at a faster rate than the more stable trans-isomer.

The experimental results reveal that the highest yields of methylcyclopropane (6 .0 to 10 .1$) were obtained from magnesium and the dihalobutanes. Methylcyclopropane was formed in smaller yields, both from 1,1-dichlorobutane and sodium in decalin (3 .9$) and from 1,1-dibromobutane and zinc-copper couple in diethyl Carbitol (1.9$) or dimethylformamide (1.8$). Reactions in which diethyl

Carbitol was a solvent produced butane in 10 to 15.6$ yield while those in which decalin was used gave only 1.2 to 3.7$ butane. The experiments in dimethylformamide proceeded without the usual induction period observed in other experiments involving zinc-copper couple or mag nesium. However, since a greater percentage of butane

(31$) was produced in this reaction, it can be concluded that dimethylformamide was a better source of hydrogen

for reduction than were the other solvents.

Reactions of 1,1-di chloro-2,2-di.methylpropane

(1,1-dichloroneopentane) and metals were of interest since

this gem-dichloride possessed no^-hydrogen. If a carbene were formed in these reactions it would have to undergo

carbon-skeleton rearrangement in order to give olefins, or

undergo carbon-hydrogen insertion to form 1,1-dimethyl-

cyclopropane.

It was necessary to modify previous techniques for

collecting and analyzing products produced from 1,1-di

chloroneopentane and metals. Since both gases and low-

boiling liquids were formed (b.p. range ca_. -6.6 to 3 8.5°),

the composition of the products was different throughout

the reaction apparatus. The gases collected were more

concentrated in the low-boiling components whereas those 68 in the reaction vessel were richer in the high-boiling compounds. Therefore, it was necessary to sweep the reaction mixture thoroughly with nitrogen and to condense the hydrocarbon products. Samples were analyzed on a variety of columns (Table 15 in the Experimental Section); results are abstracted in Table 6.

1,1-Dichloroneopentane and sodium in decalin or hexadecane at 148° gave in 21 -28$ yield the following volatile hydrocarbons: 1,1-dimethylcyclopropane (57.0-

71.5$), 2-methyl-2-butene (14.7-22.8$), 2-methyl-l-butene

(0-1.7$), neopentane (5.0-12.8$), 2-methyl-l-butene

(0-1.7$), neopentane (5.0-12.8$), 1-butene (4.0-4.6$) and butane (1.8 to 2.7$). It was necessary to initiate the reaction of 1,1-dichloroneopentane and magnesium in di ethyl Carbitol at 190° with ethylene bromide. The follow ing products were obtained in 65^ yield: 1,1-dimethylcyclopropane (3 8.2 $), 2-methyl-2-butene (33.0$), 2-methyl-l- butene (trace), neopentane (14.3$) and 1-butene (14.5$).

Butane was not detected in the products from reaction with magnesium. The compounds formed were identified by com parison of gas chromatographic data with that from au thentic compounds (32 ).

(32). A sample of 1,1-dimethylcyclopropane was obtained from Dr. L. Friedman. TABLE 6

SUMMARY OP REACTIONS OP 1,l-DICHL0R0-2,2-DIMETHYLPR0PANE WITH METALS

Metal (°C) Na(l48) Na(l48) M g (190) Na(l48)h

Solvent*3 DLN DLN DEC HED

Per Cent Yield of Hydrocarbons0*e»* 2 id 26s 65 28S

Neopentane 6.7 12.8 14.3 5.0 1,1-Dimethylcyclopropane 71.5 57.0 38.2 65.4 1-Butene 4.4 4.0 14.5 4.6 2 -Methy1-1-but ene --- 1.7 tr. 1.7 2 -Methyl-2-butene 14.7 22.8 33.0 21.4 Butane 2.7 1.8 1.9

(a) Abstracted from detailed tables in the Experimental Section, (b) DLN- Decalin; DEC-Diethyl Carbitol; HED-Hexadecane. (c) Calculated yields were based on C5 hydrocarbons (dj Yield was calculated and analyses were performed on mixture of gases condensed from reaction; any gases in the collector tube were not condensed. (e) Analyses of samples isolated by sweeping the system with nitrogen and condensing the vapors, (f) A typical analysis; several columns were used to analyze products. (g) Small amounts of isobutylene were detected in analyses on silver nitrate- ethylene glycol column, (h) A mixture of els- and trans-di-t-butylethylene was ob tained in 5^ y i e l d .

CT\ vo 70

The products from the reactions of 1,1-dichloro neopentane and sodium or magnesium are the same as those from base-catalyzed decomposition of 2 ,2 -dlmethylpropanal tosylhydrazone (2 a,c) or from reaction of strong bases with neopentyl chloride (3b,c,e). In the latter two systems a carbenic intermediate has been postulated to undergo intramolecular carbon-hydrogen insertion to form

1 ,1-dimethylcyclopropane or carbon-skeleton rearrangement to form 2 -methyl-2 -butene.

Formation of the intramolecular products from re actions of 1,1-dichloroneopentane is illustrated as follows:

9h3

CH3 Redu M* CH3 -C-CH3 CH3-C=CHCH3^CH2= Jh3 ch3 ch3 y Oi3 Insertion 71

The formation of 2-methyl-l-butene cannot occur by a simple carbenoid process. However, in the presence of active metals small quantities of 2 -methyl-l-butene may result from isomerization of 2 -methyl-2 -butene (3 3 ).

(3 3 ) It has been reported that butenes isomerize reverslbly in the presence of active metals (31 ).

Previously in the base-catalyzed decomposition of 2,2-di- methylpropanal tosylhydrazone, formation of 2 -methyl-l- butene was postulated to arise by cationoid decomposition caused by proton donor contaminants (2a,c). Neopentane could be formed by reduction of the type suggested earlier in experiments with gem-dlhalopropanes. It is believed that the Cij. compounds detected in reactions with 1,1-di chloroneopentane were derived from an impurity (34).

(34) Although small quantities of neopentyl chloride and 1,3-neopentyl dichloride were present in the 1,1-dichloroneopentane, no other impurities were detected by gas chromatographic methods. Tt is improbable that any C4 compounds, and especially butane and l^butene, would result from the impurities detected. It is possible however that the neopentane used in the chlorination con tained butane and that a mixture of mono- and dichlorobutanes were formed in the synthesis of 1,1-dichloroneopen tane. Rearrangement does not occur during radical-chain chlorination of neopentane [P. C. Whitmore and G. H. Fleming, J. Am. Chem. Soc., 4161 (1933)]. Most of the mono- and dichlorobutanes would be removed by rectification. However, small quantities of 1,2-dichlorobutane, whose boil ing point is within one degree of that of 1,1-dichloroneo pentane, would not be separated by small scale distillations nor would it normally be detected by gas chromatographic analysis. It is therefore believed that the butane and butene were derived from 1,2 -dichlorobutane and not from reactions involving 1,1-dichloroneopentane. 72

It can be seen in Table 6 that the yield of intra molecular products from 1,l-dichloro-2 ,2 -dimethylpropane is higher with magnesium than with sodium. However, the relative amount of 1,1-dimethylcyclopropane formed in the magnesium reaction is less while that of 2 -methyl-2 - butene is greater. Perhaps at the higher temperature of the magnesium reaction— 190° in comparison to 148° for the sodium reaction— carbon skeleton rearrangement of the carbene becomes more preferential.

Since the yields of intramolecular products from

1 ,l-dichloro-2 ,2 -dimethylpropane and metals were low (21 -

28$) an attempt was made to separate and identify addition al products. In one experiment, after a prolonged sweep of the reaction system with nitrogen, a liquid was collected which corresponded to a 57$ yield of a hydrocarbon. Subse quent analysis and separation by gas phase chromatography revealed the hydrocarbon was composed of cls-dl-t-butylethylene (13$) and trans-di-t-butvlethvlene (87$). The compounds isolated possessed infrared spectra and physical properties identical to authentic samples of the els- and trans-d1-t-butylethylenes.

The 57$ yield of coupling products combined with the 28$ yield of intramolecular products accounts for 85$ of the 1,1-dichloroneopentane. It is apparent that coup ling is more favorable in reactions involving 1,1-dichloroneopentane and sodium than in reactions with the gem-dlhalopropanes and -butanes in which yields of intramolecular products are considerably higher [ca. 60%\

(35). There are several paths by which these di-t.-butyl-

- “ (35) Attempts to isolate coupling products derived from Co and C4 dihalides were unsuccessful in earlier experiments. ethylenes could be formed:

CH.

c h 3-c -c h c i 2 l ■NaCl CH3 2Na. -NaCl

?”3 Na ■ ?H3 2NaCl + CHo-C-HC 74

CH. CH- I ^ pi Ms I CH3-?-CH'ci + NaiCH-?"CH3 CH- CH- -2NaCl

Hv _ ,C(CH3 )3 CH3 CITo ;c=cv i - (ch3 )3c H 0H3-f-0HCCl + Sa'CHi - CII3 CHo CKo -2NaC:

HH SC=C' CHo CHc (ch3 )3c' c(ch3 )3 I 1 - CH3-C-CH: + :CH-C-CH3 -2NaCl CH- CHo + 2Na*

ch3 CH' CHo CH3 I J :NaCl..^. CH3-C-HCCI-HCCI-C-CH3 CH -C-CH + C1^CH”?"CH3 3 ^ 1 l CH- CH, CHo CHo

At present sufficient experimental evidence is unavailable

to determine the exact path by which the di-^t-butylethyl-

enes are formed.

Cyclobutanone tosylhydrazone reacts with sodium

methoxide in aprotic solvents to give via carbenoid

processes methylenecyclopropane (70-80$) and cyclobutene

(10-15$) and small amounts of the 1- and 2 -butenes (5**15$)

(2b,c). It was of interest then to determine if analogous

products are obtained from the reaction of 1,1-dichloro-

cyclobutane and sodium or magnesium. 75

Reaction of 1,1-dichlorocyclobutane with sodium gave in 29$ yield (Table 7) a mixture of cyclobutene

(75.6$), cyclobutane (12.5$), l,3 ~butadlene (3.7$), and methylenecyclopropane (4.3$), along with smaller amounts of ethene (2.8$) and the 1- and 2-butenes (1.1$). With magnesium in diethyl Carbitol, the same gaseous products were obtained (21 to 32 $ yield) but they were of diffej^nt composition. In these reactions, methylenecyclopropane

(51.6-55.7$), cyclobutene (31.2-35.3$), cyclobutane (8.4-

9.0$), 1,3-butadiene (1.4-2.2 $), ethene (l.0-2 .0$), propene (0 .0 to 0 .5$) and 1- and 2 -butenes (0 .5 to 1 .0$) were formed. The composition of gases formed changed with time (Table 18 in Experimental Section), and therefore the results of the analyses by vapor phase chromatography are qualitative. It has been reported (36) that methylene-

(36) J. T. Grayson, K. W. Greenlee, J. M. Derfer, and C. E. Boord, J. Am. Chem. Soc., 3344 (1953). cyclopropane on standing at 0° or above slowly polymerizes, and on "distillation leaves a sizable residue" (36).

Periodic analysis by gas chromatography of the products ob tained from reaction of 1 ,1-dichlorocyclobutane and mag nesium indicated that methylenecyclopropane was being slowly removed from the system. Under the more drastic conditions of reaction with sodium at 143° it is quite probable that most of the methylenecyclopropane polymerized before the TABLE 7

SUMMARY OP REACTIONS OP 1,1-DICHLOROCYCLOBUTANE AND METALS

Metal (°C)b Na(l43) M g (134) M g (130) M g (150)

Per Cent Yield of Hydrocarbons0 29d 22 ** 2 id 32h

Ethene 2 .8 2 .0 1.5 1.0 Propene ------0.5 0.5 1-Butene 0 .8 0 .5 0.4 0.5 trans-2-Butene 0.3 — 0 .6 0.5 Cyclobutane 12.5 9.0 9.06 8.46 Cyclobutene 75.6 35.3 31.7 31.2 l,3_Butadiene 3.7e 1.6 1.4 2.2 Methylenecyclopropane 4.3 51.6 5^.9 55.7

(a) Abstracted from detailed tables in the Experimental Section, (b) Solvents used: diethyl Carbitol with Mg; hexadecane with Na. (c) Composition of gases in reaction vessel, (d) Analvsis of products within 2 hr. after reaction, (e) Possibly contains some cls-2-butene. (f) Analysis of products within one day after reaction; traces of cls-2- butene are not resolved, (g) Possibly contains some cls-2-butene. (h) Analysis of products within 30 min. after reaction, (h) Calculated yields are based on the volumes of Cjf. gases evolved.

This secondary reaction can explain the great difference

In the amounts of methylenecyclopropane detected in the products obtained from sodium and magnesium. The percentages of methylenecyclopropane reported in Table

7 represent a minimum; the actual percentages could be considerably higher.

The principal products from reaction of 1,1- dichlorocyclobutane and metals can be explained by for mation of a carbene Which undergoes carbon-skeleton re arrangement to methylenecyclopropane or hydrogen-transfer to cyclobutene.

Carbon-Skeleto;

-Hydrogen Migration

The cyclobutane can arise from reductive processes in volving abstraction and/or exchange reactions of carbenoid or organosodium intermediates with the solvents, the gem- dichloride, and/or traces of water. l,3“Butadiene presum ably arises from collapse of the carbenic intermediate or else from isomerization of cyclobutene (37b). Ethylene may be formed by any of the following transfor mations:

There Is also the possibility that ethylene results from action of strong bases on diethyl Carbitol (3c). Thermal cleavage of cyclobutane may give 1-butene which in the presence of strong bases or active metals is isomerized to cis- and trans-2 -butenes (3 1 ).

^ CH3CH2CH=CH2 79

Thermal Isomerization of cyclobutane at 420-480° has been reported to yield ethylene principally (37).

(37)(a) F. Kern and W. D. Walters, Proc. Nat. Acad, of Sci. U. S., 3 8, 937 (1952); (b) C. T. Genaux, F. Kern, and W. D. Walters, J. Am. Chem. Soc., 73. 4498 (1951); 2 5 , 6196 (1953).

Although polymerization of the hydrocarbons formed offers a logical explanation for the low yields (21 -32 $) of products isolated from reactions of 1,1-dichlorocyclobutane and sodium or magnesium, several reaction residues were investigated in an attempt to find other products.

When mixtures from the sodium or magnesium ractions were hydrolyzed with water, the only gaseous product was hydro gen. This indicated no simple organometalllc intermediates remained. In a typical experiment involving 1,1-dichlorocyclobutane and magnesium, however, 12 $ unreacted dichloride was isolated. Yields were not corrected for recovered starting materials.

Reactions of 1,1-dichlorocyclopentane and 1,1-dichlorocyclohexane with sodium in hexadecane gave cyclopentene (94.8-95.5$) and cyclopentane (4.5-5.2 $) in 57$ yield and cyclohexene (90.7-93.6$) and cyclohexane (6.4-

9.3$) in 69$ yield respectively. There was no evidence for formation of bicyclic hydrocarbons by intramolecular carbon-hydrogen insertion (transannular) processes. Diazocycloalkanes (7-10 carbons) decompose

carbenically to give transannular derivatives and cyclo-

olefins (2e,f). Dlazocyclooctane decomposed to cls- bicyclo[3 .3 .0 ]octane (46$) and bicyclo[5.1 .0 ]octane (9$) by insertion processes and cls-cyclooctene (45$) by re

arrangement of-hydrogen (2e). It was therefore of

interest to determine if the reaction of 1,1-dichloro-

cyclooctane and sodium was similar to decomposition of

dlazocyclooctane, since presumably both reactions can in

volve a carbenlc intermediate.

Reaction of 1,1-dichlorocyclooctane and sodium in

hexadecane at 142° gave the following mixture of hydro

carbons in 60$ yield (See equation below): cis-bicyclo-

[3 .3 .0 ]octane (1 7.8$) and bicyclo[5.1 .0 ]octane (2 $)(38) by

(3 8) Bicyclo[5.1.0]octane possibly contained a small quantity of cyclooctane. Characteristic strong bands for cyclopropanes at 3.25 ^ and 9.82 y. indicated the predominance of the bicyclo derivative.

transannular insertion and cls-cyclooctene (7 0.2 $) by 1,2 -

rearrangement of hydrogen.

/ C1 'XC1 142° + 2 Na* Hexadecane -2NaCl 81

An unidentified material (7.8$) (39) was also isolated

(39) The product, nD20 1.4739* was separated by G. P. C. Its retention time was not identical to 1,3- or 1,5-cyclooctadiene. If this unknown is a single compound, its refractive index is not in agreement with that of any readily explainable material. The infrared spectra of the material could not be identified. and small amounts of several Impurities (1 .6$ total) were detected by gas-phase chromatography. A compound (0.6$) having the same retention time as 1,3-cyclooctadiene was also detected.

To ascertain whether sodium was catalyzing iso merization of the products derived from 1,1-di.chlorocyclooctane, samples of cyclooctene and blcyclo[5.1 .0 ]octane

(40) were each treated with sodium in hexadecane. When

(40) Bicyclo[5.1.0]octane was prepared by Dr. L. Friedman from cycloheptene, methylene iodide, and zinc- copper couple: b.p. l4l.8-142° (760 mm.), nD25 1.4601 (ana lytical sample). cyclooctene was heated with sodium in hexadecane at 143° for 13 hr., only cyclooctene (70.5$ recovery) was iso

lated. After bicyclo[5.1.0]octane had been treated with

sodium in hexadecane at 153° for 14 hr., the material isolated (70.7$ recovery) contained bicyclo[5.1.0]octane

(89$), cyclooctene (5.5^)* and two unidentified compounds

(5.5$), one of which possessed the same retention time as bicyclof3 .3 .0 ]octane. 82

It may thus be concluded that reaction of 1,1-di-

chlorocyclooctane and sodium and thermal decomposition of

dlazocyclooctane apparently proceed through similar or

identical carbenic intermediates. Under the more drastic

reaction conditions of sodium at 142°, the percentages of

products formed by transannular insertion processes de

crease while that from migration of ^-hydrogen becomes

greater. Isomerization by sodium of the products formed during reaction is not extensive. EXPERIMENTAL

Special Techniques

Bolling points, unless noted otherwise, were de termined as the compounds distilled. No thermometer corrections were made. Bolling points for which pressures are not recorded were taken at atmospheric pressure.

All melting points are uncorrected.

Microanalyses were performed by Galbraith Labora tories, Inc., Knoxville, Tennessee.

Infrared absorption spectra were obtained with a

Baird Associates, Inc., model B. Infrared recording spec trophotometer except for those of compounds separated by vapor phase chromatography. These latter spectra were run on a Perkin-Elmer, model 21, infrared recording spectro photometer. Potassium bromide wafers were used to de termine the spectra of solid compounds.

Preparation of gem-Dlhalldes

CX -Bromobutyryl Bromide

Bromine (880 g., 5.5 mol.) was added dropwise in

3 hr. to a stirred suspension of red phosphorus (35 g., 84

1 .1 3 mol.) and butyric acid (250 g., 2 .85 mol.; Matheson,

Coleman, and Bell, b.p. 158.5-160°) in a 3-necked flask which had been equipped with a reflux condenser, a drop ping funnel, and a mechanical stirrer (4l). After the

(41) The general procedure followed was that described for the preparation of

Bromobutyryl bromide (536.5 g.* 2.34 mol., 82$ yield), b.p. 105-108°/100 mm., lit. (42) b.p. 172-174°, was ob tained .

(42) J. Volhard, Ann., 242 141 (1887).

Ot-Bromobutyramlde

(X-Bromobutyryl bromide (268 g., 1.17 mol.) was added dropwise with stirring in one hour to cold (oa. -10°), concentrated ammonium hydroxide (500 ml.). The semisolid mixture was then stirred 15 min. and filtered. The white

solid was washed thoroughly with ice water, suction dried

for 12 hr., and vacuum dried to constant weight. Ofc-Bromo-

butyramide (163*5 g.> 0 .9 9 mol., 84$ yield), m.p. 109.5-

110°, was isolated. When the amide was recrystallized

from equal parts by volumes of petroleum ether (65-110°)

and chloroform, its melting point was raised to 110.8-

111 .1°; lit. (43)(a) m.p. 112 °, (b) 108°.

(43) (a) C. A. Bischoff, Ber., ^0, 2312 (1897); (b) R. Lespieau, Bull. soc. chim. Prance, [3]j 55 (1905).

1.1-Dibromopropane (44)

(44) 1,1-Dibromopropane was prepared by the pro cedure of C. S. Stevens, T. K. Mukherjei, and V. J. Traynelis, J. Am. Chem. Soc., 78. 2264 (1956).

00-Bromobutyraml.de (33.2 g., 0.20 mol.) was dis

solved in a solution of bromine (38.4 g., 0.24 mol.) and

sodium hydroxide (32 .0 g., 0 .80 mol.) in water (280 ml.) at

0°. The resulting mixture was stirred for 10 min. at room

temperature, heated rapidly in 20 min. to its boiling point,

and then steam distilled. Crude 1,1-dibromopropane (10.0

g., 0.05 mol., 25$ yield) was separated as a dense oil

from the first 25 ml. of the distillate. Ether was added 86 and the mixture was washed with ice water. The organic layer was separated, dried over magnesium sulfate, and distilled through a glass helix-packed column. 1,1-

Dibromopropane, b.p. 6 6.0-66.8°/80 mm., n^2^ 1.5037, lit. (44) b.p. 134-135°, nD20 1.5084, lit. (45) b.p.

(45) J. C. Conly, J. Am. Chem. Soc., 25., 1148 (1953).

86-88°/l55 mm., nD2^ 1 .5063, was isolated (46). Analysis

(46) An alternate low-temperature procedure to prepare 1,1-dibromopropane (44) from Q£-bromobutyramide was unsuccessful. The amide was added to aqueous hypo- bromite prepared .in situ. The resulting solution was cooled at 0 -5° for 69 hr. before it"was heated gradually to 50° and maintained at this temperature for 2 l/4 hr. During this time an oil settled which crystallized upon cooling. The crude white solid, m.p. 106-108°, after being recrystallized from petroleum ether-chloroform did not depress the melting point of authentic OC-bromobutyra - mide. by gas phase chromatography indicated that the 1,1-dibromo propane was greater than 99% pure (47).

(47) Analysis was performed on a 5 ft. Silicone column, T - 120°; p * 29.6 cm. helium.

1 .1-Dlbromobutane

Bromine (151.7 g., 0.95 mol.) was dropped into

stirred phosphorus trichloride (130.6 g., O .95 mol.) at 87

0 to -5°. The resulting slushy, red-orange solid was stirred for 15 min.; butyraldehyde (72.0 g., 1 .0 mol.) was then added in one hour with continued cooling. After most of the aldehyde had been added, the mixture was clear, water-white. Stirring was maintained at 0° for

6 additional hours. Then after the dissolved hydrogen bromide had been removed with a water aspirator the re action mixture was vacuum distilled through a Vigreux column (6 in.). The crude 1,1-dibromobutane (55-8 g.,

0.259 mol., 27.3^ yield), b.p. 48~58°/l2.5-14.0 mm., was washed with ice water and cold saturated aqueous potassium bromide and dried over magnesium sulfate. Upon distillation through a glass helix-packed column (1.4 by

23 cm.), 1,1-dibromobutane, b.p. 57-59°/l9.5-2 0.5 mm., nD25 1.4988, lit. (48) b.p. 158°/760 mm., 5 3 % 3 mm.,

(48) A. Kirrmann, Bull. soc. chim. Prance, [4], 41, 318 (1927). nD21 1.4991, lit. (45) b.p. 9 0.5-92°/l01 mm., nD25 1 .4980-

1.4989, was isolated. Analysis by gas phase chromato graphy (49) indicated the 1,1-dibromobutane to be more

(49) A Silicone column (5 ft.) at 110° with helium carrier gas (41.8 cm. pressure) was used for the analysis. than 99$ pure 1 .1 -Dichlorobutane

Butyraldehyde (108.0 g. 1.5 mol.) was added dropwise to stirred phosphorus pentachloride (333.3 6«> 1«6 mol.) in 2 hr. at 0 to -5°. The mixture was stirred at

0° for 2 hr. and overnight at room temperature; then it was heated to reflux and cooled. The solution was steam distilled by dropwise addition to stirred boiling water.

The dark, steam distillate was extracted with petroleum ether (30-60°); the ether extracts were washed with ice water and saturated aqueous sodium chloride and dried

over magnesium sulfate. The mixture was filtered, concen

trated, and then fractionated to yield 1,1-dichlorobutane

(72.4 g., 0.57 mol., 38$ yield), b.p. 110.5-112 .0°, nD2 7 *5

1.4300, lit. (5 0)(a) b.p. 111-114°, (b) b.p. II3-II50,

(50)(a) J. B. Hinkamp, Ph.D. Dissertation, The Ohio State University (1943); (b) V. Meyer, and P. Petrenko-Kritschenko, Ber., 25. 3304 (1892); (c) D. Tischtschenko and A. Tschurbakow, J. Gen. Chem. (U.S.S.R.), 2, 894 (1937).

20 (c) np 1.4355. Two impurities totaling 1.5$ were de

tected when the 1,1-dichlorobutane was analyzed by gas

phase chromatography (5 1).

(51) A 5_ft. Silicone column operating at a temperature of 84 and a helium carrier gas pressure of 5 2 .6 cm. was used for the analysis. 89

1 .l-Dlchloropropane

Freshly distilled propionaldehyde (116 g., 2.2 mol.; Eastman, b.p. 47-48.5°, nD23 1.3639) was added dropwise In 4 1/4 hr. to stirred phosphorus pentachloride

(208.3 g., 2.2 mol.) at 0 to -5°. The first part of the addition was complicated by a vigorous reaction which was accompanied by evolution of hydrogen chloride. This hydro gen chloride caused the aldehyde in the dropping funnel to darken and become viscous (5 2); therefore, to reduce

(52) Propionaldehyde Is readily polymerized. E. J. Buckler, J. Chem. Soc., IO36 (1937), has completed a study of the stability of propionaldehyde. the occurrence of this undesirable reaction the propional dehyde was placed in the dropping funnel in small aliquots and added dropwise. After the reaction mixture had become somewhat homogeneous, it was possible to increase the rate at which the aldehyde was introduced. Upon completion of addition of propionaldehyde, the clear, golden reaction solution was stirred for 4 hr. at 0-5° and then overnight at room temperature. The following fractions were col lected when the propionaldehyde— phosphorus pentachloride mixture was distilled through a glass helix-packed column:

(I) b.p. 31-76°, 15 g., (II) b.p. 76-96°, 152 g., (ill) b.p. 96-102°, 82 g. Fractions II and III were poured into a mixture of ice water and ether. The ethereal layer was 90 washed successively with ice water (4 times), dilute sodium carbonate (3 times) and cold saturated sodium chloride (2 times) before it was dried overnight over magnesium sulfate. The mixture was filtered and fraction ated to give 1,1-dichloropropane (8 3.1 g., 0.736 mol.,

33.4# yield), b.p. 85-86°, nD23 1.4272, lit. (53)(a) b.P.

(53)(a) K. E. Howlett, J. Chem. Soc., 945 (1953); (b) A. L. Henne, M. W. Renoll, and H. M. Leicester, J. Am. Chem. Soc., £1, 938 (1939).

8 8.1°, nD18 1.4288, (b) b.p. 8 8.3°, nD20 1.42887, of at

least 9 9.6$ purity (54).

(54) A 5 ft. Silicone column at 69° and helium carrier gas pressure of 37.6 cm. (flow rate 10 m l ./5 8 sec.) were used for the gas chromatographic analysis.

1.l-Dlchloro-2.2-dimethylpropane (l.1-Dlchloroneopentane;

A mixture of chlorinated neopentanes (5 5) was

(55) Dr. L. Friedman furnished a mixture of chlorinated products from sunlamp-induced reaction of chlorine with neopentane.

rectified at atmospheric pressure through a glass helix- packed column (1.8 by 94 cm.). Analysis by G. P. C. of

the l,l-dichloro-2 ,2 -dimethylpropane thus obtained 91 indicated it to be 90$ pure (56). Therefore, low temper-

(56) The 1,1-dichloroneopentane was analyzed on a Silicone column (5 ft.) at a temperature of 85° and helium carrier gas pressure of 52 cm. ature fractional crystallization methods and hypodermic techniques were used to further purify the desired dichloro compound. Petroleum ether (30-60°) served as the solvent.

The product was then fractionated through a glass helix- packed column (1 .8 by 24 cm.) to yield 1,1-dichloroneo pentane, b.p. 122 -123 °, nD2? 1.4-358, which when analyzed by G. P. C. appeared to b e '98$ pure (56).

1 .1-Dlchlorocyclobutane

Cyclobutanone (4-3.0 g., 0.614- mol.; Aldrich Chemi cal Company) (57) was added dropwise in 2 hr. to stirred

(37) Analysis of the cyclobutanone on a 15 ft. Carbowax 1500 column at 87 and 20 lbs/sq. in. helium pressure indicated the ketone to be 98$ pure. phosphorus pentachloride (156.2 g., 0.75 mol.) at 0 to -5°.

After approximately one quarter of the ketone had been added, the reaction mixture was a pale yellow slush; stirring was facilitated. The mixture was stirred at 0° for 6 hr. after addition of the ketone before being poured onto crushed ice (1 .5 1 .) and extracted twice with ether.

The ether extracts were washed successively with ice water 92

(6 times), dilute aqueous sodium bicarbonate (2 times), again with ice water (2 times), and finally with cold

saturated aqueous sodium chloride. Analysis of the dried

ether extract by gas chromatography showed the presence of

one major and at least 9 minor components besides ether

(5 8). After the ether had been removed, the residual oil

(5 8) Analysis was performed on a 15 ft. Carbowax 1500 column at a temperature of 122 ° and helium carrier gas pressure of 20 lbs./sq. in. (flow rate of 10 ml./l9 sec.). was fractionated through a glass helix-packed column

(13.5 by 1.1 cm.) to give 1,1-dichlorocyclobutane (39.5 g.*

0.316 mol., 51.6# yield), b.p. 70-73.5°/2l8.3 mm. Analysis

by gas chromatography indicated the dichloride to be ca.

95$ pure (5 8). Refractionation through the same column

gave 1,1-dichlorocyclobutane of 98$ purity (5 8), b.p.

73.0-73.5°/h8.5 mm., nD27 1 .4552.

Anal. Calcd. for C4HgCl2 : C, 38.43; H, 4.84, Cl, 56.73.

Found: C, 38.57; H, 5.13; Cl, 56.48.

1 .1-Dichlorocyclopentane

Cyclopentanone (200 g., 2.5 mol.) was added in

4 3/4 hr. to stirred phosphorus pentachloride (562.4 g.,

2.7 mol.) at -5°. Initially the reaction was quite vigorous

and the mixture darkened. After addition of the 93 cyclopentanone had been completed, the deep brown, homogeneous liquid was stirred for 3 hr. at 0 ° and then overnight at room temperature before being dripped into stirred ice water. To facilitate washing and to minimize

losses, the crude product was extracted with Skellysolve

F. The organic layer was separated, washed successively with ice water (3 times), dilute aqueous sodium carbonate

(3 times), ice water (one time), and finally with cold

saturated sodium chloride (2 times) before being dried

over a mixture of potassium carbonate and magnesium

sulfate. After the drying agents and Skellysolve F had

been removed, the products were fractionated through a

glass helix-packed column (1.8 by 24 cm.). A fore-run,

consisting mainly of 1-chlorocyclopehtene, distilled be

fore crude 1,1-dlchlorocyclopentane (78.5 g., 0.569 mol.,

22.8$ yield), b.p. 55-55.5°/35 mm., was isolated. Analy

sis by gas chromatography revealed that the fraction was

88$ 1,1-dichlorocyclopentane and 12 % 1-chlorocyclopentene

(59). When.this mixture was redistilled through the same

(5 9) A 5 ft. Silicone column operating at a temperature of 82 ° and a carrier gas pressure of 53 .3 cm. was used for the analysis.

column, 1,1-dichlorocyclopentane, b.p. 55°/35 mm., nD 2^ 9 4 1.4681, lit. (60) b.p. 51°/30 ran., nD25 1.4690, was

(60) M. T. Rogers and J. D. Roberts, J. Am. Chem. Soc., £8, 843 (1946). obtained which contained 7$ 1-chlorocyclopentene (59).

1.1-Dlchlorocyclohexane

Cyclohexanone (208 g., 2.0 mol.; DuPont Hytrol 0, b.p. 152.5-153.5°) was added dropwlse with stirring in

5 1 /2 hr. to phosphorus pentachlorlde (437.4 g., 2 .1 mol.). If cyclohexanone were added rapidly vigorous evolution of hydrogen chloride resulted. After all the ketone had been introduced, the deep purple solution was stirred for one hour at 0° and then overnight at room temperature before it was hydrolyzed by being added dropwise to stirred ice water. The mixture was extracted twice with ether; then the ether extracts were washed successively with ice water (3 times), dilute sodium carbonate (2 times), again with ice water, and finally twice with cold saturated sodium chloride before being dried over magnesium sulfate. The product was filtered, concentrated, and fractionated through a glass helix- packed column (1.8 by 24 cm.). A considerable fore-run, consisting principally of 1-chlorocyclohexene (124.7 g.,

1.06 mol., 53$ yield) was collected before crude 9 5 1,1-dichlorocyclohexane (5 5 .6 g., 0.364 mol., 1 8.2 $ yield), b.p. 86-87°/57-58 mm., nD23 1.4793, lit. (6l)(a) b.p.

(61)(a) B. Carroll, D. G. Kubler, H. W. Davis, and A. M. Whaley, J. Am. Chem. Soc., 78. 5382 (1951); (b) W. Kwestroo, P. A. Meijer, and E. Havinga, Rec. trav. chlm., 21, 717 (1954).

8 3.8 °/5 0 mm., nD20 1.4803, (b) b.p. 58-60°/l4 mm., was obtained.

Analysis by gas chromatography indicated that this crude product contained only ca. 75$ 1,1-dichlorocycio- hexane, the remainder being 1-chlorocyclohexene (62). Upon

(62) A 5 ft. Silicone column operating at a carrier gas pressure of 5 2 .8 cm. (flow rate of 10 m l ./3 8 sec.) and a temperature of 126° was used for the analysis. distilling this mixture through the packed column described above, purer 1,1-dichlorocyclohexane, b.p. 87°/56 mm. nD25 1.4780, was isolated; analysis by vapor phase chroma tography indicated it was still contaminated by 13$ 1- chlorocyclohexene (62)(6 3).

(63) It is possible that hydrogen chloride was eliminated from 1,1-dichlorocyclohexane during the gas chromatographic analysis. 1.1-Dlchlorocyclooctane

Cyclooctanone (126.0 g., 1.0 mol.) was added dropwise to stirred phosphorus pentachloride (254.1 g.,

1.22 mol.) at 0° in 2 l/2 hr. The resulting tan colored mixture was stirred for 2 hr. at 0° and then for one hour at room temperature before It was poured onto crushed ice (2 1.) and extracted-ifith ether. Even though the ether layer was washed repeatedly with ice water (10 times), the aqueous washings remained acidic to pH paper

(64). Finally the organic layer was washed twice with

(64) Possibly In the presence of water, hydrogen chloride is rapidly eliminated from 1,1-dichlorooctane. saturated aqueous sodium chloride and then dried over magnesium sulfate at -20°. The mixture was filtered, concentrated, and then rectified through a glass helix- packed column (1.8 by 24 cm.) to give a preliminary fraction of 1-chlorocyclooctene (87.4 g., 0.61 mol.,

61.0$ yield), b.p. 79-80.5°/l7 mm., nD25 1.4897, lit.

(65) b.p. 82 -86°/21 mm., nD 20 1.4918, and a subsequent

(65) E. A. Braude, V/. F. Forbes, B. F. Gofton, R. P. Houghton, and E. S. Waight, J. Chem. Soc., 4711 (1957). fraction consisting mainly of 1,1-dlchlorocyclooctane

(17.7 g., 0.099 mol., 9.9$ yield), b.p. 9 7 - 1 0 5 % 7 mm., 97 nD2^ 1.4967. The crude dichlorlde was refractionated

through a glass helix-packed column (1.1 by 13.5 cm.)

to obtain 1,1-dichlorocyclooctane, b.p. 75~76°/5 mm., nD26 1.4963 (66), of analytical purity.

(66) 1,1-Dichlorocyclooctane underwent decompo sition during analysis by gas chromatography.

Anal. Calcd. for CgH^Clg: C, 39.16; H, 7.79; Cl, 53.C5.

Pound: C, 39.04; H, 7.80; Cl, 53.22.

Reagents

Decalln (Eastman Tech.) was shaken with concen

trated sulfuric acid until the acid layer remained un

colored. The decalin was then washed with water and dried

and distilled over calcium hydride through a short Vigreux

column, b.p. I88-I890 .

Hexadecane (Humphrey-Wilkinson, Inc.), after being

treated with fuming sulfuric acid, was washed successively

with water and aqueous solutions of sodium bicarbonate and

sodium chloride and then dried over magnesium sulfate. The

hexadecane was refluxed over calcium hydride for several hours and then distilled, b.p. 131-132°/5 mm.

Dlethvl Carbitol (Eastman white label) was stored

over potassium hydroxide pellets for an extended period. Shortly before use, the diethyl Carbitol was decanted and then dried and distilled over calcium hydride, b.p. 186°. High purity nitrogen (General Dynamics, Liquid

Carbonics Division) was purified and dried through a

Fieser train (67).

(67) L. F. Fieser, "Experiments in Organic Chemistry," 3rd Ed., D. C. Heath and Company, Boston, 1955, P. 299.

Sodium (Mallinckrodt Anal.) was stored under high grade mineral oil. Only freshly cut sodium free of oxide

coating was used in reactions.

Purified magnesium powder (Baker) was used without additional treatment.

Samples of authentic C2 to C^ gases were obtained from the Matheson Company, Inc. Other authentic hydro carbons were obtained from Dr. K. W. Greenlee, A. P. I.,

Project 45, The Ohio State University, Dr. A. J. Streiff,

A. P. I. Research Project 58 B, Carnegie Institute of

Technology, and Dr. L. Friedman. A sample of cyclobutane was prepared by the Kishner reduction of cyclobutanone

semicarbazone (68).

(68) The procedure followed was that in "Organic Reactions," Vol. IV, John Wiley and Sons, Inc., New York, 1949, P. 390. 99

Sodium Dispersion

The procedure described in "inorganic Syntheses"

(69) was followed for preparation of sodium dispersions.

(69) T. Moeller, Editor-ln-chlef, "inorganic Syntheses," Vol. II, McGraw-Hill Book Co., Inc., New York, 1957, P. 6.

A 3-necked 250 ml. flask equipped with a metal condenser, nitrogen inlet tube, and Labline high-speed stirrer (70),

(70) Manufactured by the Labline Co., Chicago, 111. was dried and swept with nitrogen. Sodium, a solvent such as decalin, diethyl Carbltol or hexadecane (50-75 ml.), and several drops of oleic acid, a dispersing agent, were added to the flask while dry nitrogen was continuously passed through the system. The flask was submerged in an oil bath and heated to 115-120 °; then high-speed stirring was started and continued for 20 min. The stirrer was stopped, the oil bath was removed, and the mixture was cooled to room temperature without disturbance. The dis persion is then ready for subsequent reactions. 100

Reactions of gem-Dihalides and Metals

General Technique

Sodium. A 3-necked 250 ml. flask (71) equipped

(71) A Morton flask was used with the Labline high-speed stirrer whereas a special wide-necked flask was necessary with the Vibro-Mixer. Although this vibra tory mixer was developed and is manufactured in Switzer land, it can be purchased in the U. S. from the Fisher Scientific Co. with a condenser, a Labline high-speed stirrer (70) or

Vibro-Mixer (7l)> and a 10 ml. pressure-equalized dropping funnel containing a nitrogen inlet tube and a rubber septum sampling device was dried and swept with nitrogen. The solvent, decalin, diethyl Carbitol, or hexadecane (50-75 ml.), and freshly cut sodium (72) were placed in the flask

(72) Results of reactions of undispersed sodium and gem-dlhalldes were similar to those obtained in experi ments in which true sodium dispersions were used. However, at the lower temperatures (67-78°) at which the sodium dis persions were used, the percentage of cyclopropanes formed was less; total yield of hydrocarbons collected was also decreased, while dry nitrogen was passed continuously through the system. The 1,1-dihalide was placed in the dropping funnel and the nitrogen flow was stopped. The reaction flask was submerged in an oil bath and heated to the temperature selected for reaction; then stirring was initiated and the 101

1,1-dihalocompound was added dropwise. The reactions appeared to be instantaneous and'the mixtures invariably turned red immediately and then finally deep purple. The evolved gases which were collected in a tube by displace ment of a nearly saturated sodium sulfate solution were ultimately analyzed by vapor phase chromatography.

Experiments with the 1,1-dichlorides of neopentane, cyclopentane, cyclohexane, and cyclooctane were modified because of the low volatility of products formed. The hydrocarbons from these reactions were isolated by sweep ing the system with dry nitrogen and condensing the vapors in a series of traps immersed Dry Ice— acetone.

Magnesium. A 125 ml. flask, equipped with a con denser, a Teflon-coated stirring bar, and a 10 ml. pressure-equalized dropping funnel fitted with a nitrogen

Inlet tube and a rubber septum, was dried and swept with nitrogen. A gas exit tube led from the top of the con denser to a. gas cylinder filled with a nearly saturated solution of sodium sulfate. Powdered magnesium and a small crystal of iodine were placed in the flask and heated with a flame until violet vapors filled the container.

Diethyl Carbitol (5~10 ml.) was added to the magnesium and stirring was Initiated. After a solution of the 1,1-dihalocompound In diethyl Carbitol (2-4 ml.) had been placed in the dropping funnel, the reaction vessel was immersed 102 in an oil bath heated to the desired temperature for the reaction; stirring was begun. The dihalide was added slowly but usually a 1/2 to 2 hr. induction period, de pending on the dihalide and temperature employed, was characteristic of these experiments. After initiation a vigorous, gas-evolving reaction ensued, which was usually complete within 10-15 min. The gases were subsequently analyzed by gas chromatography.

Zinc-Copper Couple. The apparatus and experi mental conditions were essentially identical to those described for reactions with magnesium. The zinc-copper couple was prepared following the procedure discussed in

Part I, page 19. Only 1,1-dibromoalkanes were reacted with zinc-copper couple. A vigorous reaction accompanied by evolution of gases followed a characteristic induction period. These gases were analyzed by gas chromatographic techniques.

Analytical Procedure

Gas Chromatography. A Model A-90-C Aerograph gas

chromatographic Instrument equipped with a hot-wire type detector (helium carrier gas) and connected to a 2.5 millivolt full-span sensitivity Brown recorder was used

for the analyses. The chart speed in most of the determi nations was 12 in./4ir., but this was increased to 24 103 in./hr. in the analysis of hydrocarbons generated from

1,1-dichlorocyclobutane and 1,1-dichlorocyclooctane.

Eight chromatographic columns were employed:

A, 15 ft. 40$ Dowtherm A (l) (73)5

B, 15 ft. 35$ 3 \ 3 ^Oxydipropionitrile;

c, 15 ft. 35$ Dowtherm A (ll);

D, 4 ft. 35$ Dowtherm A — 12 ft. 35$, ethylene glycol saturated with silver nitrate.

E, 3 ft. 35$ Dowtherm A — 12 ft. 35$* ethylene glycol saturated with silver nitrate (ll).

F, 5 ft. 20$ Silicone GE SF-96 (74)

0, 15 ft. 30$ Carbowax 1500

H, 3 ft. Dowtherm A — 12 ft. 35$* ethylene glycol saturated with silver nitrate (l).

(73) A mixture of biphenyl and diphenyl ether from the Dow Chemical Company.

(74) This ready-packed column was purchased from Wilkens Instrument Co., Walnut Creekx California.

Column packings were prepared by adding an ether and/or methanol solution of the appropriate substrate to firebrick (75). The mixture was stirred until the particles

(75) The 42/60 mesh firebrick used was obtained from Wilkins Instrument Co. of firebrick appeared evenly coated; then the volatile 104 solvents were removed either under a vacuum or in a stream of nitrogen with continued agitation. The column tubing (l/4 in. outside diameter copper or refrigeration grade stainless steel) was then packed with the prepared firebrick and bent into shape. Since Dowtherm A bleeds easily even at room temperature from chromatographic columns, Column A was eventually replaced by Column D.

Hydrocarbons were identified by comparison of re tention times with those of available authentic samples.

Examination of infrared spectra furnished additional evi dence. A Dowtherm A column was used in conjunction with a

•-oxydipropionitrile column (Column B) for analyzing most of the light hydrocarbons (up to C^). Column B failed to adequately resolve small amounts of methylcyclopropane in the presence of cis- or trans-2-butenes; how ever, it possessed greater general utility since peaks were sharper and retention times were considerably less than those for the same compounds on Columns A or C.

Combination Dowtherm A — -silver nitrate columns (ColumnsD,

E and H) were useful in identification of low-boiling olefins (up to C^). Column B was used at higher temper atures for analyses of Cg compounds. Columns F and G were used in analyzing the hydrocarbons from reaction of

1,1-dichlorocyclooctane and sodium. 105

Peak areas, calculated by multiplying the peak height by the half-peak width, were used to determine the product composition of each hydrocarbon mixture. No calibration corrections were made. It has been shown that quantitative estimates of the composition of many mixtures of organic compounds can be made by using the peak areas resulting from gas chromatographic analyses (76). Since

(76) E. M. Fredericks and F. R. Brooks, Anal. Chem., 28, 297 (1956). the recorded response to all compounds in the usual range of analysis is nearly the same on a unit weight basis, the peak area is proportional to the concentration of the compound,(77). However, errors would result in the present

(77) M. Dimbat, P. E. Porter, and E. H. Stross, Anal. Chem., 28, 290 (1956). study if the thermal conductivity of a gas mixture is not linear in concentration.

Total Yield of Hydrocarbon Products. In reactions involving only gaseous products the per cent yields were calculated from the volumes of gases collected after ap propriate temperature and pressure corrections had been made. No attempts were made to correct yields for gaseous hydrocarbons formed either by coupling two molecules of the dihalide or those formed by fragmentation reactions. When both gases and low-boiling liquids were produced in a reaction, the entire apparatus was swept with nitrogen and all volatile products were collected in a series of traps submerged in Dry Ice— acetone. The yields were calculated from the weight of the condensate. In reactions in which higher-boiling hydrocarbons were generated, the same technique of purging the system with nitrogen and condensing the vapors was utilized to isolate products.

However, in these cases, the reaction vessels were heated to a higher temperature and stirred during the

sweep. The calculated yields of gaseous products are approximations and probably are accurate only to t 10^.

Reaction of 1.l-Dlchloro-2.2- dimethylpropane with Metals

In Run 15, 1,l-dichloro-2,2-dimethylpropane (7.0

g., 0.05 mol.), sodium (2.76 g., 0.12 mol.), and decalin

(75 ml.) at 148° gave only 491 ml. of gaseous products

(Table 14). Gas chromatographic analyses indicated the

composition of gases in the collection tube differed

markedly from that in the reaction flash (Table 15).

The different compositions resulted from the fact that

both gases and low-boiling liquids were formed in this

reaction (78).

(78) Analyses of vapors in heated (80-100°) re action vessels were also unreliable. 107

To obtain a more valid estimate of the yield and composition of products from l,l-dichloro-2,2-dimethylpropane and metals, the reaction apparatus was swept with nitrogen and the hydrocarbons condensed in Dry Ice — acetone. By use of techniques at low temperatures (ca.,

”75°), a small aliquot of the condensate was transferred

to another container and completely vaporized. These

vapors were considered to be representative of the

products formed and were analyzed by gas phase chromato

graphy. These analyses for Runs 16-18 are listed in

Table 15.

Since the combined yield of hydrocarbons from

intramolecular processes was low (usually 20 -30$) in the

reactions of 1,l-dichloro-2,2-dimethylpropane with metals,

an attempt was made to isolate additional products from

Run 18. A mixture (0 .7 8 g., 28$ yield) consisting mostly

of 1,1-dimethylcyclopropane was first condensed from re

action of 1,l-dichloro-2,2-dimethylpropane (5.60 g., 0.04

mol.) and sodium (2.3 g., 0.10 mol.) in hexadecane (65 ml.)

at 148°. Receivers were changed and the nitrogen sweep

was continued for ca. 3 .5 hr. A product (1.6 g., 0.0114

mol., 57.1$), m.p. ca. -10 to -12°, b.p. 124-125° (79),

(79) Boiling point was determined according to the microanalytical procedure described.by R. L, Shriner, R. C. Puson, and D. Y. Curtin, "The Systematic Identi fication of Organic Compounds," 4th Ed., John Wiley and Sons, Inc., New York, 1956, p..32. 108 nD25 i.4ioi was isolated which, when analyzed and

separated by gas chromatographic techniques, contained

87$ trans-dl-t-butylethylene, nD2<“* 1.4113, lit. (8 0) b.p.

(80) R. B. Turner and R. H. Gamer, J. Am. Chem. Soc., 80, 1430 (19^8).

125.1, nD20 1.4117 and 13$ cls-di-t-butylethvlene. nD20

1.4267, lit. (80) b.p. 143°, nD20 1.4264 (See Table 16).

Additional evidence for the structures of these olefins were obtained by comparing their infrared spectra and

retention times (G. P. C.) with those of authentic samples.

Reactions of 1.1-Dlchlorocvclobutane with Metals

Reaction of sodium (2.76 g., 0.12 mol.) and 1,1-

dichlorocyclobutane in hexadecane (50 ml.) at 143° was

rapid; a mixture of gases was isolated in 29$ yield (Table

17). The major component of this mixture was cyclobutene

(75$) along with smaller amounts of cyclobutane (12 $), methylenecyclopropane (4$), and ring cleavage products

(9%) [Table 18], However, when 1,1-dichlorocyclobutane

(3.13 g., 0.025 mol.) was mixed with magnesium (0.8 5 g.,

0.035 mol.) in diethyl Carbitol (10 ml.) at 134°, an

induction period of 1.5 hr. was observed before reaction was initiated. Twenty-one per cent (118 ml.) of the theo retical volume of gas was collected. Since the small 109 amount of gas collected did not give useful gas chromato

grams, vapors in the reaction vessel were analyzed. It

is apparent (Table 18, Run 21) that the composition of

these gases change with time. Within a half-day after

completion of the reaction the per cent composition of methylenecyclopropane obtained decreased from 5^ .9 to

^3 .8$ while the relative percentages of other components

increased. The reaction with magnesium and 1,1-dichloro

cyclobutane was repeated (Run 22) to check further this

change in product composition; the per cent methylene

cyclopropane decreased from 5 5.7$ immediately after re action to 37$ after 27 hr.

Since the yields of gaseous products were rela

tively low in .reactions of 1,1-dichlorocyclobutane with metals, special efforts were made to isolate additional products. Reactions flasks from Runs 19 and 21 were swept

completely free of volatile hydrocarbons; then the re action residues were slowly hydrolyzed with water. The

gas collected and analyzed in each case was hydrogen generated from reaction of the metals with water. Before being extracted with n-pentane, the hydrolyzed mixture

from Run 21 was treated with dilute hydrochloric acjd (3$) to dissolve magnesium salts. The pentane extract was washed successively with ice water (10 times) to remove diethyl Carbitol and then with cold, aqueous saturated 110 sodium chloride. After the organic layer had been dried over magnesium sulfate, most of the n-pentane was removed through a glass helix-packed column (13.5 by 1.1 cm.).

Analysis of the residue on the Carbowax 1500 column,

T = 128°, flow rate 10 ml./21.8 sec., indicated the presence of only one component, 1,1-dichlorocyclobutane, besides n-pentane. The identification of 1,1-dichloro cyclobutane was based on its retention time, refractive index, and infrared spectra. The unreacted dichloride remaining was calculated from gas chromatographic data to be O .36 g., 12$ recovery.

Reaction of 1.1-Dichlorocyclopentane With Sodium

Reaction of 1,1-dichlorocyclopentane (11.0 g.,

0.08 mol.) with sodium (4.6 g., 0.20 mol.) in hexadecane

(65 ml.) at l40° gave crude cyclopentene (3 .09 g.* 0.046 mol., 57$ yield), nD27 1.4172, lit. (8l) nD20 1.42246,

(81) "Selected Values of Physical and Thermodynamic Properties of Hydrocarbons and Related Compounds," A. P. I. Research Project 44, Carnegie Press, Pittsburgh, 1953* P. 64. nD25 1.41940. Gas chromatographic analysis indicated the presence of ca. 5$ cyclopentane. Retention times of cyclopentane and cyclopentene were identical to those of au thentic samples. Ill

Reaction of 1,1-Dlchlorocvclohexane with Sodium

A mixture of 1,1-dichlorocyclohexane (12.23 g.,

0 .08 mol.), sodium (4.6 g., 0 .2 0 mol.), and hexadecane

(65 ml.) was heated at 145°, Crude cyclohexene (4.52 g.,

0.055 mol., 69# yield), nD27 1.4437, lit. (82 ) nD20

(8 2 ) Ibid.. p. 65.

1.44654 was isolated. Gas chromatographic analysis revealed that the cyclohexene contained 6-9# cyclohexane. No other compounds were present. Retention times of authentic samples of cyclohexane and cyclohexene were identical to those of the reaction products.

Reaction of 1.1-Dichlorocyclooctane with Sodium

1,1-Dichlorocyclooctane (7.0 g., 0.039 mol.) was added dropwise in one hour to sodium (2 .3 g., 0 .10 mol.) in hexadecane at 142°. After addition of the dichloride had been completed, the temperature of the oil bath was lowered to 120 °; stirring was continued for 2 hr. before the reaction flask was swept with nitrogen. Analysis by gas chromatography of the hydrocarbon condensate (2.56 g.,

0.023 mol., 60.4# yield) indicated it contained cyclooctene

(70#), bicyclo[3 .3 .0 ]octane (18#), an unidentified 112 compound A (8$), bicyclo[5.1.0]octane (1-2$), cyclooctane

( < 1$), and 1,3-cyclooctadiene (0 .7$) along with three un identified minor components (1.7$) [See Table 20], The refractive index and infrared spectra of each major compound present were determined from samples separated by gas chromatographic techniques (Carbowax column). The following refractive indices were recorded: bicyclo[3 .3 .0}- octane, nD20 1.4621, lit. (8 3) n^1® 1.4629; unidentified

(8 3J J. W. Barrett and R. P. Linstead, J. Chem. Soc., 436 (1935). compound A, nD20 1.4739; and cyclooctene, nD20 1.4702, lit. (84) nD25 1.4684. The presence of bicyclo[5.1.0]-

(84) A. C. Cope, R. A. Pike, and C. F. Spencer, J. Am. Chem. Soc., 13, 3214 (1953). octane was confirmed by the characteristic bands for cyclopropyl rings at 3.25 and 9.82 p. in the infrared spectra of a sample separated by G. P. C. The retention times of bicyclo[5.1.0]octane and cyclooctane were identi cal on the Carbowax 1500 column; on the Silicone column cyclooctene and bicyclo[5.1.0]octane emerged together.

The retention times and infrared spectra of the components in a known mixture (8 3) of bicyclo[3.3.0]ectane,

(8 5) This sample was obtained from Dr. L. Friedman. 1 1 3 bicyclo[5.1.0]octane, cyclooctane, and cyclooctene were

Identical to those of the reaction products (See Table 20).

Identification of 1,3-cyclooctadlene as a reaction product was based on the retention time of an authentic sample of

1,3-cyclooctadiene.

Attempted Isomerizatlons with Sodium

Cyclooctene

A mixture of cyclooctene (4.24 g., 0.039 mol.) and sodium (2.3 g., 0.10 mol.) in hexadecane (65 ml.) was heated at 143° for 13 hr. The temperature was reduced to

120° and the apparatus was purged with nitrogen. A ma terial was isolated which was shown by G. P. C. to be un changed cyclooctene' (2.99 g.j 0.027 mol., 70.5$ recovery).

Blcyclof5.1.03 octane

Sodium (1.0 g., 0.043 mol.), hexadecane (40 ml.), and bicyclo[5.1.0]octane [0 .8 2 g., 0.0075 mol.] (86) were

(86) This sample of bicyclo[5.1.0]octane was prepared by Dr. L. Friedman by reaction of cycloheptene, methylene iodide, and zinc-copper couple, b.p. 141.8-142° (760 mm,), nj)2-> 1.4601. heated at 153° for 14 hr. The apparatus was swept with nitrogen and the vapors condensed in Dry Ice— acetone. Gas chromatographic analysis of the material isolated (0 .5 8 g., 114

0.0053 mol., 70$ recovery) revealed that it contained

89$ bicyclo[5.1.0]octane (See Table 21); approximately

5.5$ had been isomerized to cyclooctene. Two unidentified compounds, one of which possessed the same retention time as bicyclo[3.3.03octane were present in about equal quantities (5.5$ total).

Introduction to Tables

A recorder chart speed of 12 in ./h r . was used in the analyses unless indicated otherwise, The chart speed was increased to 24 in./hr. for certain analyses.

Retention times recorded in the tables are expressed as units of length (cm.). These retention times can be converted to minutes by multiplying by the factor

0.984 (chart speed of 12 in./hr.) or 1.969 (chart speed of 24 in./hr.).

The following abbreviations appear In the tables:

DEC; Diethyl Carbitol

HED; Hexadecane

DLN; Decalin

DMF; Dimethylformamide

tr; trace

— ; Compound not present

? ,* Compound present but not resolved. TABLE 8

REACTIONS OP 1,l-DIBROMOETHANEa WITH METALS

Gas Vol., m l . Per Cent

Run Solvent Metal Temp. Theo. Coll. Yielde,h

lc DEC Mgb 105 672 309d 46 2f DEC Mgb 120 896 672 75 3s HED Na 115 896 654 73

(a) Eastman White Label, b.p. 106-106.5°. (b) Iodine was used as an•initiator, (c) 2.5 hr. induction period, (d) Collected during 2.5 hr. (e) Calculated yields were based on theoretical volumes of Cg gases, (f) 2 hr. induction period, (g) Reaction was instantaneous; the dibromide was added dropwise in one hr. (h) See Table 9 for compo sition of gases. TABLE 9

G. P. C. ANALYSES OF PRODUCTS FROM REACTIONS OF 1,1-DTEROMOETHANE WITH METALS8

<0 CO £ GQ cd CD P. £ 0 CD £ CL, £ £ O O, CD CD CO O £ P X (0 rH <0 cS O CD P P £ CD t>» > £ CM m >» * ^ co CD X CO P, 1 P £ r-i s O £ .£ X P -P O £ m l § CD 3 0 0) rl CO P -P CD £ • •HI £ O K O Eh (x, O W w 2 £ CL, rH o | P

(a) See Fig. 1 for typical gas chromatogram, (b) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (c) Pressure in cm. of Hg of carrier gas at head of column, (d) See Table 8 for reactants and conditions, (e) See page 103 for description of columns, (f) Expressed in cm. (g) Probably contains some ethane, (h) Analysis on Column B indicated products from Run 2 contained ca. 57.1# ethylene and 9.4# ethane, (i) Contains methylcyclopropane. (j) Contains 1-butene.~(k) Contains propane, (l) Possessed same rela tive retention time as that prepared by Dr. L. Friedman, Ph.D. Dissertation, The Ohio M State University (1959). uO Recorder Response c

fl>

~* CDQ 5 “ <: 9

o Butone 3 S’ (ft $ OQ S'3

I g CT 3 > Propene 3

ZII TABLE 10

REACTIONS OP 1,1-DIHALOPROPANES WITH METALS

Gas Vol., m l . Per Cent

Run Halide Solvent Metal Temp. Theo. Coll. Yielda

4° Bromide* DEC Mgh 96 444 190d 43 5* Chloride DLN Na 125 1120 739 66 61 Chloride DLN NaS 78 1120 627 5 6 7 Chloride* DEC Mgb 158h 896 374 42«J

(a) See Table 11 for composition of gases, (b) Iodine was used as an initiator, (c) Induction period of

G. P. c. ANALYSES OF PRODUCTS 'FROM REACTIONS OF 1,1-DIHALOPROPANES WITH METALS3

I 4 .o C rH 3 O

4 A 27 56.1 cm. % Comp. 10.0 8 1 .6 8.4 » M « 4 A 27 56.1 cm. R e t • Time* 6.6 7.7 14.7 --- 5 A 29 4-9.4 cm. % Comp. 1.7 95.9 2.4 --- 5 A 29 49.4 cm. Ret. Time 6.6 7.5 15.0 --- 6 A 26 49.4 cm. % Comp. 0.9 97.1 2.0 --- 6 A 26 49.4 cm. Ret. Time 6.7 » 7.7 14.9 --- 7 A 25 39.6 sec. % Comp. 6.3 . 88.1 5.0 0.5 7 A 25 39.6 sec. Re t . Time 6.3 7.0 14.7 3.3

(a) See Figs. 2, 3, and 4 for typical gas chromatograms, (b) Consult Table 10 for reactants and conditions, (c) See page 103 for description of columns, (d) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (e) Pressure in cm. of Hg of carrier gas at head of column, (f) Expressed in cm. a Crmtgas f yrcros rm ecin o 11Dhlpoae wt Metals. with 1,1—Dihalopropanes of Reactions from Hydrocarbons of Chromatograms Gas Recorder Response 53 5 20 25 30 35 Column: Dowtherm A (I) (I) Column: ADowtherm 1,1—DichtoropropaneItotide: Flow Rato: IOmt/396 25* Temp.: ea: MognMiuin Metal: 1 eeto Tm (Minutes) TimeRetention iue . iue 3. Figure 2. Figure 10 3 25 35 O ea: Sodium Metal: 1,1-DichloropropaneHalide: Column: Dowtherm A (I) (I) Column:Dowtherm A Pressure: 49.4 cm. 49.4 Pressure: Temp.: 26* 30 eeto Tm (Minutes) TimeRetention' 20 15 K) 5 O ep: 27* Temp.: Halid*: 1,1-Dibromopropon* — «a: Magn**iumM«tal: Column: (I) Dowtherm A Pressure: 56.1Pressure: cm. 30 2515 5 eeto Tm (Minutes) Time Retention

0 5 10 15 20

Figure 4. Figure 120 TABLE 12

REACTIONS OP 1,1-DIHALOBUTANES WITH METALS

Gas Vol., ml. Per Cent

Run Halide Solvent Metal Temp. Theo. Coll. Yielda

8d Bromide0 DEC 98 40 Mg h 1 443 3.77 9e Bromide0 DEC Zn-CuJ*J 100 432 258 62 10© Bromide0 DEC Zn-CuJ* 100 432 273 63 ll£ BromideS_. DMP Zn-Cub -» J 75 432 157 36 12 h Chloride1 DLN Na 118 1120 734 66 13 Chloridek DLN Na1 67 1120 277 25 14m Chloride0 DEC Mgb 175 896 340 38h

(a) Consult Table 13 for composition of gases, (b) Iodine was used as an initiator, (c) All the halide was present at initiation, (d) Induction period of 35 min.j gas collected during 20 min. (e) Ga. 1.5 hr. induction period; reaction could not be initiated at 75°» gas collected during 15 min. (f) No induction period. (g) Added dropwise in 15 min. (h) Reaction was instantaneous, (i) Dichloride was added in 20 min. (j) Prepared from zinc dust and aqueous copper sulfate; see page 19 • (k) Dichloride was added in one hr. (1) Sodium dispersion, (m) Ca. 2 hr. induction period; reaction could not be initiated at lower temperatures; gas collected in 15 min. (n) Calculated yields were based on theoretical volumes of C4 gases. 121

\ TABLE 13

G. P. C. ANALYSES OP PRODUCTS PROM REACTIONS OF 1,1-DIHALOBUTANES WITH METALS9

I—1 S o Temp. Carrier Gas Press.d 1-Butene Butane trans-2-Butene

o els-2-Butene « Methylcyclopropane Ethene

_ _ 8 A 25 50.3 % Comp. 15.6 73.7 10.7 « mm m 8 A 25 50.3 Ret. Timee 16.5 19.1 —- 27.2 ___ — — 9 A 28 47.6 % Comp. 10.5 87.5 —- 2.0 --- —— 9 A 28 47.6 R e t . Time 17.8 ■ 20.5 --- 29.4 B —- --- —— 9 29 ; 3? -9 % Comp. 10.6 87.4 2.0 9 B 29 34.9 Ret. Time 4.9 7.1 —— 9.1 --- 10 A 28 1 47.6 % Comp. 5.7 92.5 —- 1.8 —- -- 10 A 28 47.6 Ret. Time 17.8 20.5 — - 29.7 --- — — 11 A 28 47.6 % Comp. 31.0 67.2 — - 1.8 ---■ - 11 A 28 47.6 Ret. Time 17.7 21.0 —- 29.7 --- - 12 A 30 47.7 % Comp. 3.7 87.0 2. 4 3.9 4.0 - 12 A 30 47.7 Ret. Time 18.1 21.1 27. 4 30.9 32.1 13 B 28 40.3 % Comp.** 1.2 73.6 10.2 ? S 14.9 — — 13 B 28 35.5 Ret. Time 4.8 6.9 8.2 9.1 — — 13 B 27 36.5 % Comp.*1 1.2 26.9 28 .8 ? g 43.4 - 13 B 27 36.5 R e t . Time 5.7 8.4 10.0 11.7 - 122 TABLE 13 (Continued)

■o « <13 03 S3 03 03 03 Oi u <13 O a* S3 U <13 (X 03 03 •P O S3 as 3 1— 1 0) o PQ O •p 03 1 >» S3 Ol O a <13 1 1— 1 1 0) 03 >> CM S3 p a jC 1 03 S3 -P 031 £3 3 I 2 03 •HI -P Column0 Temp. Carrier 03 Butane . . r t . -O o l ___ W. 13 A 28 46.8 % Comp.i 1.4 64.5 11.4 22.8 13 A 28 46.8 Ret. Time 19.1 22.7 28.8 33.7 14 A 23 68.2 % Comp. 9.5 83.8 5.5 1.1 14 A 23 68.2 R et. Time 15.6, 18.3 26.5 2.9 14 H 25 53.5 % Comp. 10.43 83.8 5.8 9 14 H 25 53.5 R e t . Time 4.9, 7.4 4^9 14 D 25 77.6 % Comp. 10.1J §?:? 5.8 9 14 D 25 77.6 Ret. Time 5.0 17.2 6.9 5^0

(a) See Pigs. 5* 6, and 7 for typical gas chromatograms, (b) Consult Table 12 for reactants and conditions, (c) See page 103 for description of columns, (d) Pressure in cm. of Hg of carrier gas at head of column, (e) Expressed in cm. (f) Composition of gases in flask immediately after reaction, (g) Impossible to resolve traces of methylcyclopropane in presence of cis- and trans-2-butene on this column, (h) Composition of gases in flask 84 hr. after reaction, (i) Composition of gases in flask 15 hr. after re action. (j) Contains ca. one per cent ethene.

M ro U) a Crmtgas f yrcros rm ecin o 11Dhlbtns ih Metals. with 1,1—Dihalobutanes of Reactions from Hydrocarbons of Chromatograms Gas Recorder Rltpont* — Holide: — 1,1- Dibromobutane II aa:Zn—opr || Matal:Zinc—Copper reue 3. m I cm.Preeaure: 34.9 Column:p.p-Otydpropionitrile fm. 2* I ■ftmp.: 29* eeto Tm (Minutes) TimeRetention 0 S 10 IS 20 iue5 Fgr 6. Figure 5. Figure N 30 Holide:1,1-Dichlorobutane Prauura: 53.5 cm. 53.5 Prauura: MognesiumMetol: Column: Dowtherm Oft.) A Tamp.: 25* 25 SilverNitrate-Glycol(l2ft)(I) eeto Tm (Minutes)Retention Time 0 5 10 15 20 Halide: 1,1-DicNorobutane Column: (I) Dowtherm A Pressure: 47.7 cm. 30* Temp.: Sodium eeto Tm (Minutes)Retention Time —i —r i— i— i— O 5 40 45 SO iue 7. Figure -t=- ro TABLE 14

REACTIONS OP 1,l-DICHLORO-2,2-DIMETHYLPROPANE WITH METALS

Ylelde Per Cent

Run Solvent Metal Temp. Theo. Coll. Yield3

15° ' 1 DLN Nad 148 1120* 491* 42 15 DLN Nad 148 3.50 0.72J 21 16*1*1 DLN Na^ 148 2.80 0.73£ 26 17* DEC Mg*> 1901 3.50 2 .29J 65 18J HED Na° 148 2.80 0.78^ 28 18 HED Nad 148 2.80 1.60f*g 5 7 m, n

(a) See Table 15 for composition of low-boiling gases, (b) Iodine was used as an initiator, (c) The dichloride used was ca.. 90$ pure (G. P. C.) (d) Although reaction ap peared instantaneous gases were evolved at a slower rate than with the 1,1-dihalopropanes and 1,1-dihalobutanes. (e) Yields are expressed in grams except those marked with asterisks; in these cases yields are expressed as volumes, (f) Obtained by sweeping reaction apparatus with nitrogen and condensing the vapors in Dry Ice— “Acetone, (g) Di-Jl-butylethylene Isolated in addition to the expected low-boiling products, (h) The dlchloride used was ca. 98$ pure (G. P. C.). (l) The dichloride was added in one hr. (J) The dlchloride was added in 1.5 hr. (k) Reaction was impossible to initiate after heating 2 hr.; reaction was started c_a. one hr. later after a few drops of ethylene bromide was added as an initiator, (l) Reaction could not be Initiated at lower temperatures, (m) B.p. 124-125° (micro); nj}25 1.4101. (n) See Table 16 for composition of high-boiling products.

M ro. VJ1 TABLE 15

G. P. C. ANALYSESa OP PRODUCTS PROM REACTIONS OF 1,l-DICHL0R0-2,2-DlMETHYLPR0PANE WITH METALS

-p G <0 si a i—i i i 0 » G 0) XI X X o

o Plow Ratee 1 , cyclopropane1 K a m CM Butane C\1

15 B 27 60.2 % Comp. 6.7 71.5 4.4 14.7 2.7 ------15 B 27 60.2 Ret. T1.mef 5-2v, 10.2 8.4 19.2 5.9 B % Comp.6 ------1.2 ? ------15 27 57.9 1 9 47.7 31.7 15 B 21 57.9 # Comp.1 45.9 36.5 ------4.3 ? ------15 E 26 21.2 % Comp. 8.5h 73.5 4.4 ------14.0 9 ------___ ------15 E 26 21.2 Ret. Time ^•3 7.4 15.2 16.8 4 *3 60.2 ------16 B 27 % Comp. 1 2 -K 57.0 4.0 1.7. 22.8 1.8 16 E 26 21.2 % Comp. 15.6h 58.5 3.4 2 . 1«J 17.0 9• 3.5k 17 C 25 61.6 % Comp. 13.2 37.1 15.6 - — 34.1 ------17 C 25 61.6 Ret. Time1 10.8 25.3 13.1 —- 54.7 ------17 B 27 61.6 % Comp. 13.8 37.6 16.6 ------32.1 ------17 E 26 21.1 % Comp. 14.3 38.2 14.5 tr. 33.0 — — _ 18 C 26 20.7 % Comp. 5.7 66.4 5.5 2.2 20.1 . . . — —— 18 C 26 20.7 Ret. Time 9.4 21.7 11.3 35.4 46.6 18 B 26 61.6 % Comp. 5.0 65.4 4.6 1.7 21.4 1.9 18 B 26 61.6 Ret. Time 5.2 9.9 8.2 19.4 15.8 5.8 ------ro ON TABLE 15 (Continued)

rH rH 4) m © P< 1—1 > > £ 1 1 0 » g K C •H P t a) S i JC 0) JC g . 0) n 0 -P p p £ p 0 3 P, 56 P. 1 rH 2. a) a) cd a> H S O 0 rH O © £ £ p £ 3 O 0) 1—1 •> 1 1 l 1 K O Ert fa 1 55 rH O 1—i C\J CVI m CVJ

18 E 26 21.1 % Comp. 5.5 65.7 5.6 1.8 17.8 3.6 18 E 26 21.1 Ret. Time 4.3 7.4 14.9 21.9 16.6 9.2

(a) Unless noted otherwise, analyses are of condensed products which had been completely vaporized, (b) See Pigs. 8 and 9 for typical chromatograms, (c) Consult Table 14 for reactants and conditions, (d) Columns used are described on page 103. (e) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (f) Expressed in cm. (g) Gfes from collection tube, (h) Contains small amount of butane, (i) Gas from reaction flask, (j) Retention time on Column E, 22.2 cm. (k) Retention time on Column E, 9.3 cm. (l) Possessed same retention times as components in authentic mixture obtained from Dr. L. Friedman. Figure 8. Gas Chromatograms of Hydrocarbons from Reactions Reactions from Hydrocarbons of Chromatograms Gas 8. Figure Recorder Response 5 5 0 O 5 10 15 0 2 5 2 0 3 35 0 4 5 4 Column: (3, (3, p'-Oxydipropionitrile Column: ep: 27* 7 -2 6 2 Temp.: lw ae lm.is c s# lOml.^i Rate: Flow f ,-ihoo22Dmtypoae ih Metals. with l,l-Dichloro-2,2-Dimethylpropane of ansu (u 17) (Run Magnesium oim Rn 18) (Run Sodium oim Rn 15) (Run Sodium eeto Tm (Minutes) Time Retention

- © - - D K 128 iue . a Crmtga o Hdoabn fo Ratos of Reactions from Hydrocarbons of Chromatogram Gas 9. Figure Recorder Response ,- clr-,—Dmtypoae ih Sodium. with Dimethylpropane ichloro-2,2— l,l-D 40 Column: Dowtherm A (3ft) (3ft) Column: ADowtherm Pressure: 53.5 cm. 53.5 Pressure: Temp.: 26* Silver (I2ft)(l) Nitrote-Glycol 35 eeto Tm (Minutes) TimeRetention 30 25 20 . a . a ao 1 i 61 & N —, A 9

U o> 129 G. P. C. ANALYSES OF HIGH-BOILING PRODUCTS FROM REACTIONS OF l,l-DICHL0R0-2,2-DIMETHYLPR0PANE WITH METALSa

1 rH 1 f>3 rH -P 3 -P Si 3 1 •o S t -PI 1 <0 O «H at rH St & a > » a 0 cat s i ca s i (U 1—1 •Hi -P u -p « Eh o | a> - p

18 F 95 35.7 % Comp. 12.6 87.4 18 F 95 35.7 Ret. Time 8.7 5.5 18 G 98 28.8 % Comp. 12.7 87.3 18 G 98 28.8 Ret. TimeS 21.0 9.5

(a) See Figs. 10 and 11 for typical chromatograms, (b) Consult Table 14 for re actants and conditions, (c) Columns used are described on page 103. (d) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (e) Sample separated by G. P. C. np20 0f 1.4267 and Infrared spectra agree with authentic sample obtained from A. P*0I. Project 5 8 B, Carnegie Institute of Technology, (f) Sample separated by G. P. C.; nj)20 of 1.4113 and infrared spectra agree with authentic sample obtained from A. P. I. Project 5 8 B, Carnegie Institute of Technology, (g) Chart speed increased to 24 in./hr. for this analysis. Gas Chromatograms of High-Boiling Hydrocarbons from Reactions of l,l-D ichloro-2,2-D im ethylpropane ethylpropane im ichloro-2,2-D l,l-D of Reactions from Hydrocarbons High-Boiling of Chromatograms Gas ih Sodium. with Recorder Response 25 >» Column: Corbowox 1500 1500 Corbowox Column: lw oe 1 l/ ^ 8 8 ml./2 10 Rote: Flow 98* Temp.: 20 eeto Tm (iue) eeto Tm (Minutes) Time Retention (Minutes) Time Retention iue 0 Fgr II. Figure 10. Figure CM 25 0 ep: 95* Temp.: _ Column: Silicone Silicone Column: Flow Rote: 10 m l./35 7 sec. 7 l./35 10 m Rote: Flow 20 15 m 10 5 0 U) M M I I TABLE 17

REACTIONS OF 1,1-DICHLOROCYCLOALKANES WITH METALS

Yield8 Per Cent

Run Chloride Solvent Metal Temp. Theo. Coil. :

1,1-Dichlorocyclobutane HED Na 143 1120 325 29b 20f 1,1-Dichlorocyclobutane DEC Mge 134 560 123 22$

2 if,h,i 1,1-Dichlorocyclobutane DEC Mge 130 560 118 2 ib 22^ 1,1-Dichlorocyclobutane DEC Mge 150 560 179 32 b 2 3 J 1,1-Dichlorocyclopentane HED Na 140 5.44* 3.09*,n 5 7 c 24J 1,1-DIchlorocyclohexane HED Na 145 6.56* 4.52*>° 69° 25k 1,1-Dichlorocyclooctane HED Na 142 4.24* 2.56* 60<3

(a) Yields with asterisks are in grams; others are expressed in ml. (b) Consult Table 18 for analyses of gas. (c) See Table 19 for analyses of products, (d) For compo sition of products, consult Table 20. (e) Iodine was used as Initiator; induction periods of from one to 2 .5 hr. were observed; reaction is complete ca.. 15 min. after initiation; all of the dihalide was present at time of initiation* (f) 1,1-DIchlorocyclobutane was 98.3”98.8$ pure, (G. P. C.). (g) Reaction was instantaneous; the dichloride was added drop-wise in 30 min. (h) No hydrocarbons were formed (G. P. C.) upon hydrolysis of resi due in flask, (i) Residue was hydrolyzed and extracted with n-pentane; unreacted 1,1- dichlorocyclobutane (O.36 g., 12# recovery) was isolated, (j) Reaction was instantaneous; 1,1-dichloropentane, ca. 87# pure (G. P. C.), was added In 2 hr. (k) Reaction was instan taneous; 1,1-dichlorocyclooctane was added dropwise in one hr. (n) n r f il 1.4172. (o) nj)27 1.4437.

M U) ro TABLE 18 v G. P. C. ANALYSES OF PRODUCTS3 FROM REACTIONS OF 1,1-DICHLOROCYCLOBUTANE WITH METALS*3

1 0 cd 1—1 c ' CD 0 CD o' u G 0) CD CD G G •H (0 a> *o 1 -P -p cO •o OJ 3 ■p 1 £> 0 K> O 0 & 1—f G rH 1—1 0 CO O 0 CO >s % Temp. propane1* Flow Flow Ratee Methylenec

0 Propene

K 1-Butene Ethene -P O O iH m_B 19 C 28 16.0 % Comp.*1 2.8 0.8 0 .3 12.5 75.6 3.7s 4.3 19 C 28 16.0 Ret. Timef'° 3.0 --- 18.2 23. 0 38.7 33.3 25.9 43.0 19 B 26 39.5 % Comp.i 6.3 t r . 1.1 0. 5 11.9s 74.0 2.3 3.8 19 B 26 39.5 Ret. Time 5.2 7.5 11.0 12. 9 14.8. 18.5 22.5 28.5 20 C 27 16.0 % Comp.J 2.0 --- 0.5 — - 9.0 35.3 1.66 51.6 20 C 27 16.0 R e t . Time 3.0 --- 18.1 — - 38.6 34.1 25.9 42.5 20 B 27 39.0 % Comp.J 1.9 tr. 0.5 — - 9.5s 35.0 1.6 51.4 20 B 27 39.0 Ret. Time 5.2 --- 11.1 — - 15.0 19.0 22.7 27.7 21 B 27 39.0 % Comp.*1 1.5 0.5 0.4 0.6 9.0S 31.7 1.4 54.9 21 B 27 39.0 Ret. Time 5.2 7.8 11.0 12. 9 14.8 18.6 22.3 26.8 21 C 26 16.0 % Comp.J 2.5 --- 0.8 tr • 8.6 42.5 1.88 43.8 21 C 26 16.0 Ret. Time 3.0 --- 18.3 — - 38.8 3^.3 26.1 42.8 21 B 26 38.8 % Comp.J 2.3 tr. 0.9 0. 5 9 l3 g 42.2 1.8 43.0 21 B 26 38.8 Ret. Time 5.2 7.5 11.2 13. 2 15.3 19.3 23.1 28.4 22P B 28 39.5 % Comp.1* 1.0 0.5 0.5 0 .5 8.46 31.2 2.2 55.7 22P B 28 39.5 % Comp.1 1.2 0.2 0.6 0. 5 9.48 33.8 1.9 52.5 22P B 28 39.3 % Comp.m 1.4 0.2 1.0 0 .6 it). 66 37.1 46.9 m 2.3 u> TABLE 18 (Continued)

t (D 0 G O 1—1 CD o ' G G 0 -P CD (D CD CD \ G G •H 0 CD CO CD •o CD P (D 1 p p CO G G 'O cO cd G OJ G G p CD CD K CD G >co 2 ft £ <1) ft G 1—1 rH 1 JS ft rH 6 0 P 0 m CO 0 O 0 0 p 0 O 0 1—i P 1 G >> >» 1 CD G O Eh ft W Ph ■—1 P 0 O 1—i S ft

22 B 28 39.3 Ret. Time 5.2 7.6 11.0 13.1 14.9 18.8 22.5 27.5 22P B 27 39.0 % Comp.n 2.1 0.2 2.3 0.9 12.0 4l.8 3.7 37.0

(a) Products analyzed were from reaction flask, (b) Typical chromatograms are shown in Figs. 12 and 13. (c) See Table 17 for reactants and conditions, (d) Consult page 103 for description of columns, (e) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (f) Expressed in cm. (g) Impossible to resolve from cis-2-butene on this column, (h) Within 2 hr. after reaction, (i) Next day. (j) Same day! (k) 30 min. after reaction, (l) 2.5 hr. after reaction, (m) 8.5 hr. after reaction, (n) 27 hr. after reaction, (o) Chart speed increased to 24 in./hr. for all analyses in this table, (p) Flask submerged in bath heated to 110° for 27 hr. after reaction, (q) Retention time Is identical to that of a sample of cyclobutane prepared by Kishner reduction of cyclobutanone semlcarbazone. (r) Possessed same! relative retention times as authentic com pounds prepared by Dr. L. Friedman, Ph.D. Dissertation, The Ohio State University (1959). iue 2 Gs hoaorm o Hdoabn fo Ratos f ,-ihooylbtn wt Metals. with 1,1-Dichlorocyclobutane of Reactions from Hydrocarbons of Chromatograms Gas 12. Figure Recorder Response 540 45 i i 35 02 20 25 30 lw ae I0ml Rate: Flow (Run 20) Magnesium Metals: Column: Dowtherm A (H) (H) A DowthermColumn: ep: 26-28* Temp.: eeto Tm (Minutes) Time Retention ansu (Run21) Magnesium oim (Run19) Sodium ./|6 Sec 15 10 i k Figure 13. Gos Chromatograms of Hydrocarbons from Reactions of 1,1-Dichlorocyclobutane 1,1-Dichlorocyclobutane of Reactions from Hydrocarbons of Chromatograms Gos 13. Figure Recorder Response 35 ih Magnesium. with . r.otrRato —— Hrs. 2.5 Reactionofter ® 7 Hrs. ofter 27 eaction R ® % lw ae IOml./ Rate: Flow ep. 27-28* Temp.. Column: (3,p'-0«ydlproplonitrile . r.otrRato - Hrs. 8.5 Reaction otter 30 9 3 o 25 5 9 3 _ ------g#c eeto Tm (Minutes)Retention Time 20 Ol 15 10 us 5 - ® h J I— d>— ... 136 o TABLE 19

G. P. C. ANALYSES OF PRODUCTS FROM REACTIONS OF 1,1-DICHLOROCYCLOPENTANE AND 1,1-DICHLOROCYCLOHEXANE WITH SODIUMa

0 fit G rH 2 0 Temp. Carrier Carrier Gas Press.e Cyclohexane

K Flow Rate^ or Cyclohexene

0 Cyclopentane Cyclopentene

23 B 25 40.1 sec. % Comp.s 5.2 94.8 23 B 25 40.1 sec. Ret. Timef 14.5 24.8 23 B 27 50.5 cm. % Comp.h 4.5 95.5 23 B 27 50.5 cm. R e t . Time 14.5 24.7 24 B 68 40.1 sec. % Comp.S 6.4 93.6 24 B 68 40.1 sec. R e t . Time 10.9 20.0 24 B 71 52.4 sec. % Comp.h 9.3 90.7 24 B 71 52.4 sec. Ret. Time 10.4 20.1

(a) Typical chromatograms are shown in Figs. 14 and 15. (b) See Table 17 for reactants and conditions, (c) Consult page 103 for description of columns, (d) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (e) Pressure in cm. of Hg of carrier gas at head of column, (f) Expressed in cm. (g) Liquid sample, (h) Vapor sample. a Crmtgas f yrcros rm ecin o 11Dclrccoetn ad ,-ihooylhxn wt Sodium. with 1,1-Dichlorocyclohexane and 1,1-Dichlorocyclopentane of Reactions from Hydrocarbons of Chromatograms Gas Recorder Response 45 035 40 Halide: M-Didilorocyclohexone M-Didilorocyclohexone Halide: Column: p, Q—Oxydipropionitrile p, Column: lw ae 10 ml./^Qj Rate: Flow Temp.: 8 6 30 eeto Tm (iue) eeto Tm (Minutes) Time Retention (Minutes) Time Retention 25 iue 4 Fgr 15. Figure 14. Figure 0 2 O 55 50 540 45 ep: 25* Temp.: Holide: oun p —Oxydipropionitrile p p, Column: lw oe IOml./ Rote: Flow 35 1 , 1 -Dichlorocyclopentane 025 30 4 | sec. | o 20 TABLE 20

G. P. C. ANALYSES OF PRODUCTS FROM REACTION OF 1,1-DICHLOROCYCLOOCTANE WITH SODIUM3

1 0 I O CO 1 . P X 0 s 1—1 O rH m e <1) O CO +3 l>5 1 - a «——» •» p 1—1 p O •—v y 0 ^ 0 O 0 0 to g § « •ri O CD rH 0) 0 > lO r 0 a • O PQ • G 0 O G 0 0 » CO 1—1 l G rH rH & 0 5 col * - P S O P 0 CO CD O O CD ■—1 O "HI CO 0 0 •H O !>» •v "H ^ 3 O Eh &T t o Ol*— < 0 O m 0 O rH T3 O

25 G 90 18.8 % Comp. 17.8 7.8 2.06 70.2 0.6 ? 1__ *6hh 25 G 90 18.8 Ret. Timee,x 15.1 18.0 20.0 23.3 29.9 20.0 25 G 119 19.0 % Comp. 1.81 17.7 7.9 1.96 70.4 0.7 ? 25 G 119 19.0 Ret. TImef ___ i 15.8 18.1 19.9. 22.3 27.8 19.9 25 F 73 22.5 % Comp. 1.4 18.6 8.9 ? J 70.1 ? 1.0 25 F 73 22.5 Re t . Time 6.6 11.4 10.1 14.7 14.7 6.6 15.8

(a) Typical chromatograms are shown in Figs. 16 and 17. (b) See Table 17 for reactants and conditions, (c) Consult page 103 f°r description of columns, (d) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (e) Expressed In cm. (f) Chart speed increased to 24 in./hr. for this analysis, (g) Impossible to resolve from cyclooctane. (h) Represents 3 unknown compounds with retention times of 4.0, 8.9, and 11.8 cm. (i) Represents 3 unknown compounds with retention times of 5.2, 9.9, and 13.0 cm. (j) Impossible to resolve from cyclooctene. (k) Retention times were identical to those in an authentic mixture prepared by Dr. L. Friedman, (l) Sample was separated by TABLE 20 (Continued)

G. P. C.,-nD2<> 1.4621; infrared spectra was identical to that of known compound. (m) Sample was separated by G. P. C., nD20 1.47395 infrared was taken but could not be identified, (n) Although it was impossible to resolve from cyclooctane, infrared spectra was taken; compound was identified by characteristic bands for cyclopropyl rings at 3.25 ju and 9.82 ji. (°) Infrared spectra of sample separated by G. P. C. was identical to that of authentic sample of cyclooctene; nj)20 1 .4702. (p) Compound was identified by comparison of retention time with that of known sample of 1,3-cyclo- '' octadiene. 041 a Crmtgas f yrcros rm ecin o 11Dclrccocae ih Sodium. with 1,1-Dichlorocyclooctane of Reactions from Hydrocarbons of Chromatograms Gas Recorder Response 30 to 20 1— 1 o eeto Tm (Minutes) Time Retention iue 16. Figure 10 oun Croo 1500 Corbowox Column: lw ae Im.i gee. IOml./ig Rate: Flow ep: 119® lemp.: 40 35 o 30 m eeto Tm (Minutes) Time Retention 2525 1 — 1 iue 17. Figure o.. 20 oun Silicone Column: Temp: Temp: lw oe IOmL/ Rote:Flow 3 7 ° .5 2 2 Sec. M -F=- M TABLE 21

G. P. C. ANALYSES OF PRODUCTS FROM TREATMENT OF BICYCL0[5.1 .0]0CTANEa WITH S0DIUMb

1 r— » 0• ri 0) T3 • c i CO <— 1 i—i s' 0 S O -P 0 o d) 1—1 •H O >» Run o s il PQ O 0 26 G 130 22.4 % Comp. 3.0 2.5 8 8 . 8 5.6 2 6 B 130 22.4 • Ret. Timee 15.4 16.4 19.1 21.5

(a) Bicyclo[4.1.0]octane, prepared from cycloheptene, methylene Iodide, and zinc-copper couple, was obtained from Dr. L. Friedman, (b) Bicyclo[5.1.0]octane (0*82 g.) sodium (1.0 g), and hexadecane (40 ml.) were combined and heated for 14 hr. at 153 J 0*58 g. (70.7$ recovery) of a mixture was Isolated, (c) Consult page 103 for description of column, (d) Time in sec. for evolution of 10 ml. of carrier gas from exit tube, (e) Expressed in cm; chart speed increased to 24 in./hr. (f) Compound possessed same re tention time as bicyclo[3.3.0]octane under identical conditions.

ro- * = ■ AUTOBIOGRAPHY

I, Raymond S. Shank, was born in Findlay, Ohio, on December 26, 1931. I received my secondary education

(Liberty High School) in the public school system of

Hancock County, Ohio. After spending the first two years of my undergraduate training at Findlay College,

Findlay, Ohio, I transferred in 1951 to The Ohio State

University which granted me the Bachelor of Science degree in 1953. After serving two years on active duty in the United States Army, I entered the Graduate

School at The Ohio State University. I was awarded a

Teaching Assistantship in the Department of Chemistry where I completed the requirements for the Master of

Science degree which was conferred in March, 1958.

While fulfilling the requirements for the degree Doctor of Philosophy I continued as a Teaching Assistant until

October, 1959. Since that time I have been supported both as a Research Fellow and Fellow through grants made available from The Ohio State University Development

Fund, the Petroleum Research Fund of the American Chemical

Society, and the National Science Foundation.

143