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 diastereo-selectivity and high enantioselectivity. Using this method, the "bay region" substructure of the angucycline natural product arenimycin was prepared.