Enantioselective Organo-Singly Occupied Molecular Orbital Catalysis: The Carbo-oxidation of Styrenes

The first enantioselective organocatalytic carbo-oxidation of styrenes has been accomplished using singly occupied molecular orbital (SOMO) catalysis. Geometrically constrained radical cations are generated from the one-electron oxidation of enamines formed from the condensation of aldehydes with a secondary amine catalyst. These SOMO-activated radical cations are susceptible to attack by commercially available styrenes, forming y-oxyaldehyde products with uniformly high levels of asymmetric induction. Broad latitude in both the aldehyde and styrene scope is readily tolerated. This report highlights the potential of SOMO catalysis to enable the development of entirely new classes of asymmetric reactions that have no traditional catalytic equivalents.