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Xerox University Microfilms 300 North Zeob Rood Ann Arbor, Michigan 48106 76-3544 SQÜOSS, Francis Michael, 1948- THICFHENOL PROTQDBlERiCURATION. The Ohio State University, Hi.D., 1975 Chemistry, organic Xerox University Microfilms, Ann Arbor, Michigan48 ioe -ruiie rMCCco*rA-ri#*\M u a c dcezm R/!ir«orMriiancn cvai^ti v ac Dc/>ci\/cn THIOPHENOL PROTODEMERCUEATION . DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Francis M. Schloss, B.S. ***** The Ohio State University 1975 Reading Committee: Approved by Professor R. J. Ouellette Professor M. S. Newman Professor H. Shechter D . Adviser Department of Chemistry To my Parents 11 ACaCNOWIEDOÎENTS The author wishes to thank Professor Robert J. Ouellette for his suggestion of this problem and for his invaluable guidance during the course of this investigation. iii VITA February 28, 1948 ............. B o m - Cincinnati, Ohio 1970 ... .................. .. B.S., Xavier University, Cincinnati, Ohio I97O-I9 7 5................ Teaching Assistant, Department of Chemistry, The Ohio State Univer­ sity, Colnmhus, Ohio FIEIDS OF STUDY Major Field: Organic Chemistry Studies in Organic Chemistry. Professors Gideon Fraenkel, John Swenton, Robert Ouellette, Paul Gassman, Derek Horton, and Jack Hine. Studies in Inorganic Chemistry. Professors Sheldon Shore and Daniel Leussing. Studies in Analytical Chemistry. Professor James Watters. Studies in Physical Chemistry. Professor George MacWood. Iv TABLE OP CONTENTS Page DEDICATION........................................ li ACKNOWLEDOtENTS ................. ....................... .. «. iii VITA ................ :..... iv LIST OF TABLES ....................................... vi LIST OF FIGURES ................................. vii Chapter I. PROTODEMERCURATION OF ORGANŒERCURIAIS .... 1 Introduction ............... 1 Results and Discussion......... .... ........... 4 II. STEREOCHEMISTRY OF OEGANCHERCURIAL REDUCTIONS .......... 18 Introduction ......... 18 Results and Discussion............. 21 III. UTILITY OF ORGANOMERCURIALS IN ORGANIC SYNTHESIS ........ 29 Introduction......... 29 Results and Discussion ................... JZ IV. EXPERIMENTAL ............ 46 V. APPENDIX..................... ..................... 103 BIBLIOGRAPHY ............................... 11? LIST OP TABLES Table Page 1; Thlophenoxyorganomercurials...... 5 2. Effect of Thiophenol Concentration on % Yield ...... 10 3. % Yields of Thiophenol Protodemercurations .............. 12 4. Effect of Radical Inhibitors on Thiophenol Protodemercuration . 1? 5. Stereochemistry of Thiophenol Protodemercuration ........... 25 6. % Yield of Sulfides from Thiophenoxyorganomercurials...... 34 7» % Yield of Mercuric Chlorides from Thiophenoxyorganomercurials. 37 8. Results of Thermolysis of Thiophenoxyorganomercurials with Allyl Compounds ............ 44 vi LIST OF FIGURES Figure Page 1. Thiophenoxymercuricyclohexane ...................... 104 2. 1-Phenyl-3-thiophenoxymercuripropanê ............ 105 3. Thiophenoxyuierciirinorhômane ......... 106 4. 2,2-Dimethyl-4-thiophenoxymercuributane ................... 10? 5. 1-Phenyl-3“thiophenoxymercTiripropanol ...... 108 6. a-Thiophenoxymercuri-p-chlorotoltiene .......... 109 7. Thlophenoxymercuribenzene ...... 110 8. Thiophenoxymercuriethane ..... Ill 9. a-Thiophehoxymercuritoluene ......................... 112 10. 0ls-8-thiophenoxymercuridibenzoblcyclo(2.2.2)octadien-7-ol acetate .................. 113 11. Trans-8-thiophenoxy7nercuridibenzobicyclo(2.2.2)octadien-7-ol .. 114 12. Trans-8-thiophenoxymercuridibenzobicyclo(2.2.2)octadien-7-ol acetate......... 115 1 3 . Erythro-a-thiophenoxyinercuri-P-methoxy-a,8-dlphenylethane ..... II6 vii CHAPTER I PROTODEMERCURATION OF ORGANCMERCURIAIS Introduction Organomercurial reductions with substitution of hydrogen for mer­ cury are known as protodemercurations. There are quite a variety of methods which can be employed to effect such a transfonnation. Of these, examples of the most common are reductions of the organomercurial, 1 2 2 3 type R H ^ (X = halogen), with sodium amalgam ’ , sodium borohydride hydrazine^, triethyl tin hydride^, lithium aluminum hydride^, and protic acids.Each of these methods has advantages and disadvantages, but what they all seem to have in common is their lack of universality and possible undesirable side reactions that occur during the protode­ mercuration. A method that is not as well known is the reduction of diarylmercury compounds by thiophenol. Leandri and Spinelli^^ report that diphenylmercury and thiophenol are converted into thiophenoxymer- 0Hg0 + JZfSH ------> 0HgS0 + 0H curibenzene and benzene. Refluxing thiophenoxymercuribenzene in acetic acid was reported to give mercury phenyl mercaptide and phenylmercuric acetate. 1 0Hg30 + HOAc ----- > jZfHgOAc + Hg(S0), 11 In addition to aromatic sutstltutlon, Koton reported that similar reduction could he effected using saturated organomercury salts. Dessy and Paullk12 reported that treatment of phenylmercuric acetate with thiophenol to yield benzene reacted so quickly, that they were unable to obtain kinetic data on the system. Cysteine and glutathione, both 13 are amino acids containing the -SH group, are reported to decompose a number of simple organomercuric chlorides in the presence of acid. The thiols were stated to have apparently accelerated the decomposition, iZj, especially when run under acidic conditions. Jensen and Belloli on investigation of the effects of thiophenol on dialkylmercurials and thio­ phenoxyorganomercurials, determined the stoichiometry of the reaction and EgHg + 0SH > RHgSJzJ + RH RHgg0 + JZfeH > Hg(8)^g + RH the relative rate of reaction of thiophenol with different organomer- curlals. The thiophenol protodemercuration seems to belong In a class of reactions by itself. While very little is known about the mechanistic 1«5 pathway of the reduction process, Beck ^ In a study of acid cleavage of organomercurlals found that thiophenol reductions occurred under much milder conditions and faster than strong acid reductions. Thiols seemed to effect demercuration under radical conditions, not ionic; consequently the following series of equations were proposed. jfe. + HgHg ----- » R* + RHgS0 j 0S* + RH^0 ------ > R* + Hg(S0)g ( R. + 0SH ----- > RHtJZfe* In short other than what has teen described above, little is known about the general utility of this protodemercuration reaction on a variety of systems or the conditions needed for effective reduction, the stereochemistry resulting after replacement of the mercury by hydro­ gen, or any possible and undesirable complicating side reactions that might interfere with the reduction process. It is the goal of this project to attempt to answer some if not all of these questions. Results and Discussion The protodemercuration reaction ifas investigated placing emphasis, on a more complete study of the reduction on a variety of structural type molecules, and those conditions required for their reduction hy thio­ phenol. The reaction seemed to occur test when X was a phenylthio R H ^ + IÉ0 ----- > RH ■+ ifeHgX jlj, moiety rather than a halide. ' Consequently all protodemercurations studied were based on the reaction of thiophenol with thiophenoxyorgano­ mercurials and not organomercuric halides. The desired organomercurials were synthesized ty either of two major pathways. An organic halide after conversion into a Grignard, can he mercurated \ iy exchange of the magnesium with mercuric bromide or chloride under conditions for the formation of a monoalkyl product. RX + Mg ---- > R