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Calcatelli, Alessio (2025) Advances in Bismuth-Mediated Arylation and Phosphorus Redox Catalysis. PhD thesis, University of Nottingham.

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Abstract

Following the recent growth of organopnictogen synthetic methods, there has been a renewed interest in organobismuth compounds as alternatives to transition metal catalysts for the electrophilic arylations of weak nucleophiles. At the same time, rationally designed phosphorus manifolds have emerged as powerful redox catalysts that have been implemented in numerous transformations.

The work detailed in this thesis aims to contribute to the advances of Group 15 chemistry by focusing on two areas: the development of bismuth-mediated arylation reactions for the synthesis of valuable quaternary amino acids (Chapters 2 and 3) and the mechanistic investigation and synthetic application of a novel phosphorus-catalysed Staudinger reaction (Chapter 4).

Chapter 1 offers a theoretical background on the reactivity of phosphorus and bismuth, with a focus on the ligand coupling reaction, the key elementary step in all the projects of this thesis.

Chapter 2 describes the development of an electrophilic bismuth-arylation of a phosphonium enolates (Kukhtin Ramirez intermediate). The reaction offers a modular access to α,α-diaryl amino esters from readily available α-keto esters. However, despite the broad scope, the reaction lacks stereocontrol over the newly formed quaternary centre.

Chapter 3 focuses on expanding the scope of the previously discussed methodology while introducing diastereocontrol in the Bi-mediated arylation. To achieve this, the arylation of αnitro compounds in combination with L-proline tert-butyl ester as auxiliary was explored. Subsequent reduction of the nitro group would lead to the formation of an arylated quaternary amino acid. Preliminary investigation on the diastereoselective arylation of amino acid imines will also be presented.

Ultimately, Chapter 4 outlines the studies on a P(III)/P(V) catalytic Staudinger reaction. By leveraging the reactivity of a bifunctional phosphine, a tandem catalytic reduction-amidation sequence was developed. Moreover, kinetic studies provided insights into critical aspects of the catalytic cycle, such as the impact of catalyst poisoning as phosphine oxide and the key role of Brønsted bases in accelerating the reaction rate.

Item Type:	Thesis (University of Nottingham only) (PhD)
Supervisors:	Ball, Liam Ross, Denton
Keywords:	Redox Catalysis, Organobismuth compounds, Bismuth-mediated arylation
Subjects:	Q Science > QD Chemistry > QD241 Organic chemistry
Faculties/Schools:	UK Campuses > Faculty of Science > School of Chemistry
Item ID:	80340
Depositing User:	Calcatelli, Alessio
Date Deposited:	01 Apr 2025 08:50
Last Modified:	01 Apr 2025 08:50
URI:	https://eprints.nottingham.ac.uk/id/eprint/80340

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