Contemporary challenges in synthetic organic chemistry require innovative solutions. The discovery of highly-effective and readily accessible scaffolds drives the ever expanding scope of catalytic transformations. This dissertation outlines the repurposing of 1,5-Diaza-3,7-diphosphacyclooctanes (P₂N₂) ligands, commonly employed in inorganic or coordination chemistry, towards organic cross-coupling reactions. Despite their prominence in energy-storage applications, P₂N₂ ligands have been underexplored in catalytic C-C bond formation reactions. Chapter 1 provides a detailed introduction to late transition metal catalysis and the history of P₂N₂ ligands. Chapter 2 outlines the discovery of P^(Cy)₂N^(ArCF3)₂ as a powerful P₂N₂ ligand for the Ni-catalyzed reductive cross-coupling of aryl iodides with aldehydes. Chapter 3 details the extrapolation of the Ni/P^(Cy)₂N^(ArCF3)₂ catalyst system to the related, but less established, redox-neutral α-arylation of primary alcohols. Chapter 4 highlights the applicability of P₂N₂ ligands towards Ni- and Pd-catalyzed Mizoroki-Heck reactions. High-throughput experimentation (HTE) indicated a range of hits with P₂N₂ ligands compared to established ligands in Heck-type couplings. We discovered that absolute site selectivity of C-C bond formation could be controlled by simply altering the phosphorus substituent on the P₂N₂ ligand for the coupling of aryl triflates with styrenes. Notably, this degree of selectivity was not observed with conventional ligands. Chapter 5 focuses on the preparation of the P₂N₂ ligands. Finally, chapter 6 offers a perspective on future developments of P₂N₂ ligands and the prospective directions of their application in transition metal-catalyzed transformations.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/45891 |
| Date | 26 January 2024 |
| Creators | Isbrandt, Eric |
| Contributors | Newman, Stephen G. |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Attribution-NonCommercial-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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