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Approaches to quaternary carbon centres using organoboron chemistry

Jones, Dyfyr Heulyn 2013. Approaches to quaternary carbon centres using organoboron chemistry. PhD Thesis, Cardiff University.
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Abstract

The main focus of the work contained within this thesis was to explore the possible use of novel organoboron chemistry in generating quaternary carbon centres, with the ultimate aim of developing new routes for the asymmetric synthesis of chiral quaternary carbon centres. Chapter 1 contains a general introduction to the literature of organoboron chemistry, focusing particularly on organoboron reactions that contain 1, 2 - boron to carbon migrations. Chapters 2 and 3 contain attempts at generating tertiary alkyl groups bonded to boron in an asymmetric fashion. Chapter 2 specifically deals with attempts at designing a chiral version of the dichloromethyl methyl ether (DCME) reaction, giving disappointing results most probably due to the instability of the chiral analogue of DCME. Chapter 3 focuses on attempts at designing a chiral version of the cyanidation reaction. Although the generation of tertiary alkyl groups next to boron was shown to be possible when using imidoyl chlorides as the acylating reagent for relatively unhindered trialkylboranes, alkene side-products predominated when using hindered trialkylboranes – which meant that the reaction was unlikely to become an efficient method for the asymmetric generation of tertiary alkyl groups bonded to boron. Chapter 4 contains a detailed investigation into the migration of tertiary alkyl groups in the reaction between tertiary-alkyl boronic esters and (bromomethyl)lithium. As well as gaining a better understanding of the factors at work in this potentially highly important reaction, the reaction was applied to a number of highly hindered boronic esters. Chapter 5 deals with attempts at tertiary alkyl group migration using 3-chloro-1-lithiopropyne, which were in general disappointing due to the apparent instability of the intermediate ‘ate’ complex. Chapter 6 contains novel work on the migration of alkyl groups using the previously unreported 1-lithio-3-chloropropene organolithium reagent. The reaction was successfully applied to the migration of several alkyl groups (including tertiary), giving the corresponding 3-alkylprop-1-en-3-ols in good to excellent yields.

Item Type: Thesis (PhD)
Status: Unpublished
Schools: Chemistry
Subjects: Q Science > QD Chemistry
Funders: EPSRC
Date of First Compliant Deposit: 30 March 2016
Last Modified: 14 May 2020 08:40
URI: http://orca.cf.ac.uk/id/eprint/50197

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