Enantioselective Dearomatization of Naphthol Derivatives with Allylic Alcohols by Cooperative Iridium and Bronsted Acid Catalysis

The combination of a transition-metal catalyst and organocatalyst was designed to achieve a highly enantioselective system for the allylic dearomatization reaction of naphthols with racemic secondary allylic alcohols. The desired beta-naphthalenones, bearing an all-carbon quaternary center, were obtained in good yields with high chemo- and enantioselectivities. The cooperative catalytic system, involving a chiral iridium complex and phosphoric acid, provided measurable improvements in yields, and chemo-and enantioselectivities relative to single-catalyst systems. Control experiments indicated that the chiral iridium complex functions as a key species in the control of the absolute configuration, thus enabling the formation of both beta-naphthalenone enantiomers by simply employing opposite enantiomeric ligands.