| الوصف: |
Catalysts are critical to the production of desirable chemicals and materials that are used to manufacture goods which are essential to our modern economy. Efforts to decrease our reliance on precious metal catalysts has led to the proliferation of main group species and the development of the chemistry of frustrated Lewis pairs (FLPs). While the literature is dominated with reports of strong Lewis acids based on Group 13 elements (e.g. Al, B), Group 15, namely phosphorus-based Lewis acids, are emerging as viable alternatives. The graduate work presented in this thesis expands the scope of phosphorus-based Lewis acids to encompass more robust, yet reactive species for applications in catalysis and FLP chemistry, allowing access to unprecedented reactivity for electrophilic phosphorous cations (EPCs). The first chapter of this thesis details the exploration of fluoro pyridiniumphosphonium mono- and dications as efficient Lewis acid catalysts for a range of Lewis acid-catalyzed organic transformations. Following is the second chapter, which explores the synthesis of more robust EPCs and their applications in catalysis and as initiators for the Mukaiyama-Aldol condensation reaction. In the third chapter, P3-trimethylated tricationic species, accessed from the well-known triphos ligands, are synthesized and their catalytic capabilities are explored in reductive amination reactions. As well, preliminary results are presented wherein C-F bond activation and functionalization are also realized with these robust EPCs. The application of phosphorus(V)-based Lewis acids is then expanded to encompass FLP chemistry, wherein the last chapter discloses the synthesis and reactivity of rare all-phosphorus based FLPs. The reactivity of these FLPs has been exploited in E-H (E = Si, B, C, H) bond activation reactions. Initial attempts to develop related N/P FLPs have also been discussed. ; Ph.D. |