Our laboratory is exploring alternative approaches to use organometallic chemistry in catalysis. For example, Lewis acid tethered ligands have become of growing importance in the discovery of new metal-based reactions of relevance to catalysis. While a diverse range of these systems have been reported, they typically incorporate Lewis acids with linker units to the metal coordinating atom. This can both introduce the potential for chelation of the Lewis acid to the metal (via the formation of 5- or 6-membered chelate rings), and can make it challenging for the acid to assist transformation near the metal center. As an alternative, we have been actively developing new Lewis-acid tethered phosphino-imines and pyiridine-imines which frustrate any direct metal-Lewis acid interactions by removing the tethering unit. We are currently probing the use of these ligands in catalysis, where the Lewis acidic site may act in concert with the metal center to assist in a range of transformations, including the activation of inert bonds to functionalization, assisting in traditional catalysis (hydrogenation or carbonylation), or even in asymmetric catalysis.
