DIVERGENT MECHANISTIC PATHWAYS IN A METAL-CATALYZED HYDROACYLATION REACTION, AND THE ROLE PLAYED BY A HEMILABILE P-O-P LIGAND

Abstract

The project described here involves a computational mechanistic analysis of an intermolecular hydroacylation reaction with an alkene and a beta-S-substituted aldehyde. Two products are formed in the reaction, a ketone and an ester, and the calculated reaction pathways that lead to these products begin with the same set of initial steps but diverge at a point midway through the cycle. A key component in the catalysis is the role played by the hemilabile chelating phosphine ligand. Our analysis reveals that the oxygen of the ligand remains consistently bound to the metal, and that this binding affords one of the phosphines to dissociate and thereby open up a coordination site. The divergence point allows for the coordination of two different substrates to the open coordination site. If the alkene coordinates, a ketone is ultimately produced. If a second equivalent of aldehyde coordinates , an ester is produced. The full, multi-step reaction pathways will be presented.