Boron-Tethered Auxiliaries for Directed C-H functionalisation of Aryl Boronic Esters: Feasibility Studies

Hughes, Gareth (2022) Boron-Tethered Auxiliaries for Directed C-H functionalisation of Aryl Boronic Esters: Feasibility Studies. Doctoral thesis, University of East Anglia.

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Abstract

Transient Interactions between a pinacol boronic ester and bifunctional template, bearing a Lewis basic moiety, were investigated to assess the feasibility of performing directed C-H functionalisation on organoboronic esters whilst maintaining the boronic moiety.

Quantitative conversion was detected for alkoxides coordinating to a fluoroaromatic pinacol boronic ester, characterised by 1H, 19F{1H} and 11B NMR, observing a general up-field shift, which is indicative of boronate formation.

DFT calculations (B3LYP/6-31G*) elucidated that steric factors outweigh trends in pKa-H, rendering tert-butoxide more weakly binding (47 kcal/mol) than methoxide (63 kcal/mol). Synthesis of templates was performed and coordination of these bifunctional alkoxide templates to fluoroaromatic pinacol boronic esters was demonstrated.

A high-throughput screening protocol was developed, utilising GC-MS to rapidly assess the components of crude mixtures. No desired product was observed in these studies but they directed work towards polydentate ligand-substrate binding. A series of N-templated iminodiacetic acid (TIDA) ligands were designed.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Chemistry
Depositing User:	Chris White
Date Deposited:	28 Mar 2023 13:33
Last Modified:	28 Mar 2023 13:33
URI:	https://ueaeprints.uea.ac.uk/id/eprint/91698
DOI:

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