Shabbir, Usman Hamza;
(2024)
Novel approaches to Boron-directed
functionalisation of organic molecules.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis is aimed at exploiting the potential of boron compounds for: developing novel boron-directed C–H functionalisation; the synthesis of novel five-membered heterocyclic boron ring systems and in the design of a method for mono-N-methylation of primary amines. Chapter 1 provides an introductory review of the synthetic uses of boron and the medicinal applications of boron-containing compounds. Chapter 2 begins with a detailed overview into transition-metal catalysed directed C–H functionalisation. This is followed by an investigation of existing and novel boron scaffolds for their suitability in transition-metal catalysed functionalisation of unreactive C–H bonds. Various well-established directing groups (DGs) were incorporated leading to B(DG)-linked scaffolds which were then attached to a range of unsaturated and saturated aliphatic and cyclic systems containing inert C–H bonds. After extensive investigation into regioselectivity transforming inert C–H bonds to more attractive C–C bonds, it was found that a fine balance needed to be struck between B-scaffold stability and reactivity towards C–H functionalisation conditions. Chapter 3 opens with a review in the role of boron as part of a frustrated Lewis pair (FLP) as well as its applications in metal-free chemical transformations. This is followed by an investigation into the use of halomethylboronates in the synthesis of novel heterocyclic systems, through acting as a FLP. This novel reaction was optimised, and 3 different vectors of functional group attachment were explored resulting in a diverse spectrum of highly functionalised boron-centred spiro compounds. The use of halomethylboronates in the mono-N-methylation of primary amines was also studied to identify how to overcome the low methylation yields previously reported in the group.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Novel approaches to Boron-directed functionalisation of organic molecules |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2023. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Education UCL > Provost and Vice Provost Offices > School of Education > UCL Institute of Education UCL > Provost and Vice Provost Offices > School of Education > UCL Institute of Education > Centre for Languages and Intl Educatn |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10188779 |
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