Fig. 1: Background information about asymmetric synthesis of helical fluorenones.

A Rhodium(I)-catalyzed enantioselective intermolecular double [2 + 2 + 2] cycloaddition. B Palladium(II)-catalyzed carbonylative reaction using optically pure binaphthol sulfonate as the starting materials. C Kinetic resolution of helical fluorenones and synthesis of helical phenanthrenones via enantioselective homologation.