Enantioselective Ruthenium-Catalyzed Benzocyclobutenone–Ketol Cycloaddition: Merging C–C Bond Activation and Transfer Hydrogenative Coupling for Type II Polyketide Construction

The first enantioselective intermolecular metal-catalyzed cycloadditions of benzocyclobutenones via C–C bond oxidative addition are described. In the presence of a ruthenium(0) complex modified by (R)-DM-SEGPHOS, tetralone-derived ketols and benzocyclobutenones combine to form cycloadducts with complete regio- and diastereoselectivity and high enantioselectivity. Using this method, the “bay region” substructure of the angucycline natural product arenimycin was prepared.