Lewis acid mediated reactions of silyl-substituted methylenecyclopropane and N-acyliminium ions

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Description/Abstract

This thesis is concerned with Lewis acid mediated inter- and intramolecular reactions of silyl-substituted methylenecyclopropane with N-acyliminium ions, towards the formation of novel heterocyclic compounds.

Chapter 1 contains background information on synthetic organic chemistry relating to methylenecyclopropane, Lewis acids, N-acyliminium ions and related inter- and intramolecular reactions.

Chapter 2 describes the Lewis acid mediated intermolecular additions of silyl-substituted methylenecyclopropane to various substituted pyrrolidinone based N-acyliminium ions. The introduction, and subsequent removal, of an N-chiral group into the pyrrolidinone moiety is detailed. This N-chiral group has the effect of influencing the facial selectivity of the attack of the methylenecyclopropane and hence, the diastereoselectivity of the reaction.

Chapter 3 presents the attempts made to influence the reactivity of the silyl-substituted methylenecyclopropane towards electrophiles by constraining the silicon into a four or five membered ring. The synthesis of a novel silyl-substituted bismethylenecyclopropane compound is described.

Chapter 4 details the synthesis and intramolecular cyclisation studies of silyl-substituted pyrrolidinone precursors to generate novel heterocyclic compounds.