Abstract
The use of cobalt as a catalyst for Suzuki-Miyaura cross-coupling reactions to form biaryl products is explored in this thesis. The introduction and literature review describes the historical significance of catalysis, and metal catalysed cross-coupling. The importance of cheaper, more sustainable catalysis instead of the use of precious metal catalysis is discussed. After follows a review of the progress toward earth abundant catalysed cross-coupling. The review focusses on iron and then cobalt with an emphasis on the Suzuki reaction and other cross coupling reactions with soft nucleophiles. The review ends on the present day where the experimental work for this project picks up in the following chapters.In Chapter 2 a robustness screening, based on the reported screening by Glorius, was carried out. Functional group tolerances of the cobalt catalysed Suzuki cross-coupling reaction as reported by Bedford in 2021 were tested. A novel ligand robustness screening was also carried out to test for any ligand types that would prevent any heterocoupled conversion in the cobalt catalysed Suzuki reaction. The reaction was found to tolerate a range of functional groups and the results largely matched Tailor’s substrate scope reported in the 2021 paper and her doctoral thesis.
Chapter 3 describes the synthesis of two bidentate ligands based on the scaffold of the best performing ligand, IPr.HCl. The two ligands were made using functional groups known to not damage yield from the ligand robustness screening. Unfortunately, both ligands proved unsuccessful in generating more than one turnover of heterocoupled product. In addition, the synthesis of the free carbenes of the ligands in order to synthesise isolated cobalt complexes were attempted unsuccessfully.
| Date of Award | 6 Dec 2022 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Robin B Bedford (Supervisor) & Ian D Bull (Supervisor) |
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