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Gold-catalysed reactions of Nitrogen containing molecules

Martin, Nicolas (2010)
Ph.D. thesis, University of Birmingham.

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Abstract

The development of several new gold-catalysed reactions are described. Two new strategies have been employed to access pyrroles by the cycloisomerisation of alkynyl aziridines, and the formation of α,β-unsaturated imides by the oxidation of ynamides has been developed. A rare gold-mediated vinylidene rearrangement of brominated or silylated alkynes has been used to prepare brominated or silylated 2,4-substituted pyrroles regioselectively. The practical applicability of this process was limited by instability of products under the reaction conditions. Cationic gold catalysis was used in a synthesis of 2,4- and 2,5-substituted pyrroles from alkynyl aziridines. The role of counterion in these processes was studied and shown to be important in determining reaction outcomes. A Ph\(_3\)PAuCl/AgOTs catalyst system, allows 2,5-substituted pyrroles to be regioselectively synthesised in an atom-economical manner in near quantitative yield. From the same aryl-substituted starting materials the 2,4-substituted pyrrole isomer were accessed preferentially when a Ph\(_3\)PAuCl/AgOTf catalytic system was employed. A reaction mechanism accounting for the reaction outcome was proposed on the basis of \({^13}\)C- and deuterium-labelling studies. A new gold-catalysed synthesis of α,β-unsaturated imides was developed using a ynamide oxidation approach. Gold carbenoid intermediates can be formed regioselectively by action of an external oxidising agent, and were used in 1,2-insertion reactions.

Type of Work:Ph.D. thesis.
Supervisor(s):Davies, Paul
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Chemistry
Subjects:QD Chemistry
Institution:University of Birmingham
ID Code:1222
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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