Novel Synthesis Methods Using Phosphorus and Silicon Reagents

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Thornton, Edward Alexander (2020) Novel Synthesis Methods Using Phosphorus and Silicon Reagents. PhD thesis, University of Nottingham.

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Abstract

Chapter one describes the synthesis and application of dioxyphosphoranes in both solution and solid phase reactions. Two novel monolithic dioxyphosphoranes were prepared and their efficacy demonstrated through the cyclodehydration of a diol. Characterisation of the monolithic reagents was performed using solid-state NMR analysis. Intermolecular amine alcohol coupling reactions, using two solution phase dioxyphosphoranes, are described and efforts to overcome competitive side reactions discussed.

Chapter two focuses on work towards an unprecedented, single step, convergent synthesis of azetidines from isoxazolidines. Attempts to achieve this goal using phosphorus-based methodology similar to chapter one are described. Subsequent work exploits an alternative reductive system using phenylsilane as the reductant, in combination with [Ir(COD)Cl]2 as a catalyst. Preliminary optimisation studies ultimately furnished the model azetidine product in 41% yield. Preparation of ten isoxazolidines and the successful ring contraction of five of these is described. Mechanistic investigations elucidate the role of an amino alcohol in the process. Furthermore, the substrate controlled stereospecificity is established.

Chapter three describes work to expand the field of Staudinger-type synthesis methodology. Attempts to develop a novel amination protocol using alcohols is described. Additionally, a novel synthesis of sulfonamides using sulfonic acids has been developed and was utilised to prepare five sulfonamide products in yields up to 63%. A variant of the traceless Staudinger ligation using a sulfonate ester is also described. Using this method three sulfonamide products were obtained in yields up to 68%. Furthermore, a multinuclear NMR study has been performed, elucidating the mechanism of the reaction.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Denton, Ross M.
Mohamed, Mubina
McCreanor, Niall
Keywords: amines, organophosphorus compounds, synthesis
Subjects: Q Science > QD Chemistry > QD241 Organic chemistry
Faculties/Schools: UK Campuses > Faculty of Science > School of Chemistry
Item ID: 59917
Depositing User: Thornton, Edward
Date Deposited: 18 Oct 2023 14:07
Last Modified: 18 Oct 2023 14:07
URI: https://eprints.nottingham.ac.uk/id/eprint/59917

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