<p> The addition reaction between bicyclo[2.2.1]hept-2-en-7-one and several organolithium reagents was investigated. Saturated alkyllithium reagents, like most Grignard reagents, were shown to add preferentially to the syn-face of the ketone, while unsaturated alkyllithium reagents add preferentially to the anti-face. These results have been rationalized in terms of bimolecular attack by the former reagents and unimolecular attack by the latter reagents.</p> <p> The 7-t-butylbicyclo[2.2.1]hept-2-en-7-cation was shown to rearrange in mildly acidic media to a cation which lost a proton to yield syn-7-methyl-7-(2'-propenyl)bicyclo[2.2.1] hept-2-ene. The formation of this product can be explained by a Wagner-Meerwein migration which proceeds with retention of configuration about the C-7 cation centre.</p> <p> A series of 7-R-bicyclo[2.2.1]hept-2-en-7-radicals were allowed to abstract hydrogen from tri-n-butylstannane. When R = CH3, i-C3H7, n-C4H9, neopentyl, no stereochemical preference for syn- or anti- abstraction was observed. When R = t-C4H9, a large preference was shown for abstraction to occur on the anti-face, while when R = C6H5, syn-abstraction predominated. These observations, in the light of observations of abstraction by the bicyclo[2.2.1]hept-2-en-7-radical, are consistent with homoallylic participation of the double bond at the radical centre of the latter species. </p> / Thesis / Doctor of Philosophy (PhD)

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A variable temperature 1H, 13C, and 6Li NMR study of n-propyl-6Li-lithium showed five different aggregates, similar to that in the literature as (RLi)n, n= 6, 8, 9, 9, 9. There were also a number of additional new species, identified as lithium hydride containing aggregates. Unexpectedly, a series of 13C{1H} 1-D NMR experiments with selective 6Li decoupling showed evidence for 13C-6Li spin-spin coupling between the previously reported (RLi)n aggregates and various hydride species.

by Lawrence Tin-chi Law. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 96). / acknowledgements --- p.iii / ABSTRACT --- p.iv / CONTENTS --- p.v / ABBREVIATION --- p.vii / Chapter CHAPTER I --- METALLATION OF 8-METHYLQUINOLINE / Chapter 1.1 --- INTRODUCTION --- p.1 / Chapter 1.1.1 --- A Brief Review of Metal-Alkyl Chemistry --- p.1 / Chapter 1.1.2 --- General Considerations --- p.2 / Chapter 1.1.3 --- 8-Methylquinoline as Ligand Precursor --- p.8 / Chapter 1.1.4 --- Metallations by Organolithium Compounds --- p.9 / Chapter 1.1.5 --- Other Methods for Metallations --- p.16 / Chapter 1.1.6 --- Aim of the Present Work --- p.21 / Chapter 1.2 --- RESULTS AND DISCUSSION --- p.24 / Chapter 1.2.1 --- Reactions of 8-Methylquinoline with Organolithium Reagents --- p.26 / Chapter 1.2.2 --- Synthesis of Grignard Reagent --- p.35 / Chapter 1.2.3 --- Attempted Metal-Halogen Exchange Reaction at Low Temperature --- p.39 / Chapter 1.2.4 --- Metallation of 8-methylquinoline by Lithium Diisopropylamide --- p.40 / Chapter 1.3 --- EXPERIMENTAL FOR CHAPTER I --- p.43 / Chapter 1.4 --- REFERENCES FOR CHAPTER I --- p.53 / Chapter CHAPTER II --- SYNTHESIS AND CHARACTERISATION AND STRUCTURE OF SOME MAIN GROUP 14 ALKYLS / Chapter 2.1 --- INTRODUCTION --- p.58 / Chapter 2.1.1 --- General Aspects of Group 14 Organometallic Compounds --- p.58 / Chapter 2.1.2 --- Group 14 Organometallic Confounds --- p.59 / Chapter 2.1.3 --- Subvalent Group 14 Metal Alkyls --- p.63 / Chapter 2.2 --- RESULTS AND DISCUSSION --- p.67 / Chapter 2.2.1 --- Synthesis of Five Co-ordinated Tin (IV) Compound --- p.67 / Chapter 2.2.2 --- Molecular Structure of [Sn{8-(CHSiMe3)C9H6N}Ph2Cl] --- p.70 / Chapter 2.2.3 --- Synthesis of Group 14 Subvalent Metal Complexes --- p.74 / Chapter 2.3 --- EXPERIMENTAL FOR CHAPTER II --- p.76 / Chapter 2.4 --- REFERENCES FOR CHAPTER II --- p.79 / Chapter CHAPTER III --- SYNTHESIS AND CHARACTERISATION OF SOME GROUP 12 (ZINC AND CADMIUM) METAL DIALKYLS / Chapter 3.1 --- INTRODUCTION --- p.81 / Chapter 3.1.1 --- A General Aspect of Group 12 Organometallics --- p.81 / Chapter 3.2 --- RESULTS AND DISCUSSION --- p.88 / Chapter 3.2.1 --- Synthesis of Group 12 Organometallic Confounds --- p.88 / Chapter 3.2.2 --- Molecular Structure of [Cd{8-(CHSiMe3)C9H6N}(tmeda)Cl] --- p.91 / Chapter 3.3 --- EXPERIMENTAL FOR CHAPTER III --- p.93 / Chapter 3.4 --- REFERENCES FOR CHAPTER III / APPENDIX I / Chapter 1. --- GENERAL PROCEDURES --- p.97 / Chapter 2. --- PHYSICAL AND ANALYTICAL MEASUREMENTS --- p.100 / APPENDIX II / LIST OF SELECTED 1H NMR SPECTRA --- p.101

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Thesis (Ph.D.)--Kent State University, 2005. / Title from PDF t.p. (viewed July 25, 2006). Advisor: Paul Sampson. Keywords: organolithiums, Felkin-Anh diastereoselectivity, low temperatures, cryogenic reactor, carbohydrates, building blocks. Includes bibliographical references (p. 186-197).

This thesis describes the work carried out on the lithiation and rearrangement of N-aryl- and N-vinyl allylic thiocarbamates, with the aim of preparing a wide range of versatile tertiary thiols. The synthesis of the racemic allylic starting materials has been achieved through in situ [3,3]-sigmatropic rearrangement of O-allylthiocarbamates to their S-counterparts (II.A). The enantioselective version relies either on asymmetric metal catalysis (achiral substrates) or stereospecificity (enantiopure substrates) in the [3,3]-sigmatropic rearrangement. Lithiation followed by N to C aryl migration proceeds in generally good to excellent yields, with both electron-poor and electron-rich rings. The scope and the influence of various substituents at Cα or on the allylic double bond are presented in Section II.B.1. Section II.B.2 proposes a mechanistic pathway and details NMR studies carried out to get structural data in the α-thioallyllithium intermediates. Investigations of the stereospecificity of the rearrangement show that most rings migrate without loss of enantioenrichment in substrates bearing an unsubstituted allylic double bond (II.B.3.a). Complete enantiospecificity with all rings has been achieved in thiocarbamates bearing a cyclohexyl-substituted double bond (II.B.3.b). Section II.C reports the results obtained in the N to C transfer of non-aromatic groups. Excellent enantiospecificities have been achieved in the migration of a vinyl substituent, although yields remain moderate. Higher yields can be obtained but they come along with lower enantiomeric ratios. Section II.D details the transformations undertaken in the rearranged tertiary allylic thiocarbamates. A wide range of tertiary thiols has been obtained with good to excellent yields. Functionalisation of the allylic double bond in these hindered substrates was not straightforward. Eventually, ring-closing metathesis in S-allyl sulfides allows the preparation of biologically interesting 2,5-dihydrothiophenes bearing a highly enantioenriched quaternary centre. Finally, evidence for retentive aryl migration in allylic thiocarbamates is outlined in Section II.E. Circular dichroism experiments were carried out in the derivatised 2,5-dihydrothiophenes and compared with predictions obtained via DFT calculations for both enantiomers of a model compound. The absolute configuration of the 2,5-dihydrothiophenes and their tertiary thiocarbamate precursors has been unambiguously established, confirming a retentive pathway in both aryl and vinyl migrations.