This dissertation has been 65-4598 microfilmed exactly as received CARTLEDGE, Frank Kehrer, 1938- COMPARISONS OF ORGANIC GROUP IVB LITHIUM COMPOUNDS. Iowa State University of Science and Technology Ph.D., 1964 Chemistry, organic University Microfilms, Inc., Ann Arbor, Michigan COMPARISONS OF ORGANIC GROUP IVB LITHIUM COMPOUNDS by Frank Kehrer Cartledge A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Organic Chemistry Approved: Signature was redacted for privacy. In Chargé of Major Work Signature was redacted for privacy. Head of Major Department Signature was redacted for privacy. Iowa State University Of Science and Technology Ames y Iowa 1964 ii TAJBLE OF CONTENTS Page INTRODUCTION 1 HISTORICAL 3 Analysis of Organolithium Compounds 3 Cleavage of Alkoxysilanes 6 Relative Reactivities of Organic Group IVB Lithium 9 Compounds Organic Poly tin Compounds 14 Methods of preparation 15 Physical properties 21 Chemical properties 24 EXPERIMENTAL 32 Analysis of Organolithium Compounds 34 Double titration procedure 34 Reaction with triphenyltin chloride 34 Reactions of organic halides with lithium 35 ethoxide and phenoxide Cleavage of Alkoxysilanes 35 Preparation of starting materials 35 2-Cyclohexen-l-yloxytriphenylsilane 36 Crotyloxytriphenylsilane 36 Cleavages with triphenylsilyllithium 37 Allyloxytriph enyl s ila ne 37 Benzyloxytriphenylsilane 38 Ethoxytriphenylsilane 38 (Diph enylmeth oxy) triph enyl s ila ne 39 2-Cyclohexen-1- yloxytriphenyl s ilane 39 iii Page Cleavages with lithium 40 Benzyloxytriphenylsilane 40 (Diph enylm e thoxy) triph eny1 s ilan e 41 2-Cyclohexen- 1-yloxytriphenylsilane 42 Crotyloxytriphenylsilane 42 Relative Reactivities of Group IVB Lithium Compounds 43 Reactions of triphenyltinlithium 43 With pyridine 43 With azobenzene 43 With 4,4 ' - bis (dimethylamino)benzo- 44 phenone With benzophenone 44 Competitive reactions for _n-butyl chloride 45 Infrared analysis of product mixtures 45 Triphenylsilyllithium and triphenyltin- 46 lithium Triph enylg ermyllithium and triph enyltin- 48 lithium Triphenyltinlithium and triphenyllead- 48 lithium Triphenylsilyllithium and triph enyIg er myl- 49 lithium Triph enyl s ilyllith ium and methyldiphenyl- 49 silyllithium Methyldiphenylsilyllithium and dimethyl- 50 ph enyl s ilyllith ium Competition of triphenylsilyllithium and tri- 51 ph enyIg ermyllithium for ri-hexyl chloride Reaction of methyldiphenylsilyllithium with 52 n-butyl chloride Reaction of dimethylphenyl s ilyllithium with 52 n-butyl chloride Metalations of fluorene 53 By triphenylsilyllithium 53 General procedure for comparative reactions 54 iv Page Preparations and Reactions of Organic Group IVB Lithium 54 Compounds Pentaphenyldisilanyllithium 54 Preparation of reagent 54 Reaction with ji-butyl chloride 55 D imethyl-_2- toly1 s ilyllith ium 56 Preparation of starting materials 56 Chlorodimethyl-^-tolylsilane 56 ly2-Di-2-tolyl-l, lf2 ;2-tetramethyldi- 57 silane Preparation of reagent 57 From disilane (attempted) 57 From chlorosilane 58 Dim ethyl-^- m eth oxy ph eny1 s ilyllithium 5 8 Chlorodimethyl-£-methoxyphenylsilane 5 8 Preparation of reagent (attempted) 59 Dim e thyl-£- ph enoxyph enyl s ilyllithium 59 Chlorodim ethyl-£- ph en oxy ph enylsilane 59 Preparation of reagent (attempted) • 60 2-Biphenylyldimethylsilyllithium 60 2-Biphenylylchlorodimethylsilane 6 0 Preparation of reagent (attempted) 61 Triethylgermyllithium (attempted) 61 Tri-n-butyltinlithium 62 Preparation of reagent 62 Stability in tetrahydrofuran 63 Reaction with _n-butyl chloride 63 V Page Reaction-with iodobenzene 63 Reaction with trimethyl phosphate 64 Reaction with hexaphenyldisilane (attempted) 64 Methyldiphenyltinlithium 65 Preparation of methyltriphenyltin 65 From triphenyltin chloride and methyl- 65 lithium (attempted) From triphenyltinlithium and trimethyl 65 phosphate Methyldiphenyltin chloride 66 From methyltriphenyltin and hydrogen • 66 chloride From methyltriphenyltin and chlorine 67 From methyltriphenyltin and iodine followed 67 by hydrolysis and treatment with hydro­ chloric acid Preparation of reagent 68 Stability in tetrahydrofuran 68 Reaction with trimethyl phosphate 68 Dimethylphenyltinlithium 69 Preparation of starting materials 69 Dim ethyldiph enyltin 69 Dimethylphenyltin chloride 70 Preparation of reagent 71 Branched Chain Polytin Compounds 71 Preparations of tetrakis(triphenylstannyl)tin 71 From triphenyltinlithium and stannous 71 chloride followed by triphenyltin chloride vi Page From phenylmagnesium bromide and stannous 72 chloride " From phenyliithium and stannous chloride 74 (attempted) From triphenyltinlithium and stannic 74 chloride From triphenyltin chloride, stannic chloride, and 75 lithium From bis(triphenyltin)magnesium and stannous 76 chloride followed by triphenyltin chloride Reactions of tetrakis(triphenylstannyl)tin 77 With iodine (1:1 molar ratio) 77 With iodine (1:4 molar ratio) 78 With excess sym-tetrachloroethane 78 With sym-tetrachloroethane (1:1 molar ratio, 79 attempted) With excess 1,2-dibromoethane 80 With triphenyltinlithium (1:4 molar ratio) 80 With methyllithium (1:1 molar ratio) 81 Reactions of hexaphenylditin 82 With alcoholic potassium hydroxide (attempted) 82 With moist piperidine 82 With excess sym-tetrachloroethane 83 Reactions of tri s (tr iph enyl s ta nnyl) tinlith ium 83 With trimethyl phosphate 83 With methyl iodide 84 With chlorotriphenylgermane 85 With chlorotriphenylsilane 86 With tri-_n-butyltin chloride 86 With saturated aqueous ammonium chloride 87 DISCUSSION 88 Analysis of Organolithium Compounds 88 Cleavage of Alkoxysilanes 102 vii Page Relative Reactivities of Organic Group IVB Lithium 104 Compounds Branched Chain Polytin Compounds 119 Suggestions for Further Research ' 12 8 • SUMMARY 131 LITERATURE CITED 134 ACKNOWLEDGMENTS 147 1 INTRODUCTION h The chemistry of silylmetallic compounds has received consider­ able study in These Laboratories and elsewhere since the first prepar­ ations of stable silylmetallic s in 1950 and 1951 (1). These reagents, like the well known organometallic species, have a wide range of syn­ thetic possibilities. They are of fundamental interest in silicon chem­ istry, because they allow studies of the behavior of the silyl anion in solution; and, just as the study of organometallic compounds has laid the foundations of carbanion chemistry, silylmetallic reagents are being used to elucidate the properties of negatively charged silicon, Germyl-, tin-, and leadmetallic species are no less interesting than their silicon analogs, but have received much less study. In particular, relatively little attention has been centered upon the varia­ tions in properties of metallic derivatives of silicon, germanium, tin, and lead. Therefore, the present work has sought to throw light upon the relative reactivities of these reagents. The aspect of this work concerned with the analysis of organo­ metallic compounds served as a starting point. The method to be described has been successfully applied to the analysis of solutions of silyl-, germyl-, and tinlithium compounds (2), and thus has afforded the possibility of making quantitative comparisons of the reactivities of the reagents. 2 Emphasis has been placed also upon extending synthetic possi- . bilitieSf particularly with tinlithium reagents. Several new triorgano- tinlithium compounds have been prepared, and triphenyltinlithium has been used for the synthesis of a compound, tetrakis(triphenylstannyl)- tin, which is representative of a hitherto uninvestigated series of branched chain polytin compounds. 3 HISTORICAL Analysis of Organolithium Compounds There has been much interest in recent years in analytical methods for solutions of organometallic compounds. The necessity for reliable methods when structural and mechanistic studies are being carried out is obviousf and such studies are becoming increasingly common in the literature. Analytical procedures for organomagnesium compounds have been recently evaluated (3-5). In the case of organolithium compounds there have been several studies aimed at developing a simple, accurate procedure (6-16). It is well recognized that hydrolysis of an aliquot of an organolithium com­ pound followed by titration with acid (6) leads to an analysis that is always high, because of the impossibility of excluding all traces of oxygen and moisture, which react with organolithium reagents to give other basic species. Thus, the simple acid titration is measuring the combined concentrations of the several basic components of the solution. The most commonly used method of analysis for alkyllithium com­ pounds has been a double titration in which benzyl chloride is used to destroy the organolithium compound (8). Acid titration after treatment of the solution with benzyl chloride measures basic species other than the organolithium compound. The difference between the total basic 4 content and that after treatment with benzyl chloride thus corresponds to the organolithium content. The method is more convenient to carry out than other procedures proposed, but several drawbacks have become apparent. Quite low concentration values are obtained when the anal­ ysis is carried out on solutions of methyllithium and aryllithium com­ pounds, and recent work has also indicated that the analysis is some­ what low for other alkyllithium compounds as well (11, 16, 17), The implication is that benzyl chloride does not react quantitatively with an organolithium compound to give nonbasic products. It