Gold(I)-catalysed synthesis of cyclic sulfamidates by intramolecular allene hydroamination
Higginbotham, Mari C.M.
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The work reported in this thesis outlines the gold(I)-catalysed synthesis of cyclic sulfamidates by intramolecular allene hydroamination. Work carried out in an attempt to prepare a novel acyl anion equivalent is also included but endeavours were halted after one year of study. The thesis is divided into six chapters: Chapter one provides an introduction to the reactivity of gold, current metal-catalysed hydroamination reactions and allene structure, synthesis and reactivity. The current synthetic methods for the preparation of sulfamidates and their uses is also covered. Chapter two outlines the attempted use of the Burgess reagent to prepare olefinically substituted sulfamidates and the attempts to reverse regioselectivity in sulfamidate synthesis. Chapter three includes an initial proof of concept in gold(I) catalysis and an account of substrate synthesis. Allenes were synthesised by Crabbé homologation or Johnson- Claisen rearrangement reactions. The allenes were then converted to the corresponding sulfamates. Chapter four outlines our studies of gold(I)-catalysed hydroamination. This includes optimisation of catalyst and the effects of substitution on reaction rate and stereochemical hypothesis. The current scope and limitations of this chemistry is also discussed. Chapter five outlines the research work attempted within the first year of study. The work focussed on the attempted preparation of a thermally unmasked acyl anion equivalent. Chapter six provides a formal report of the experimental procedures. Stereochemical abstract: All compounds with stereogenic centres were prepared as racemic mixtures but only one enantiomer is represented in the schemes.