Asymmetric synthesis of planar-chiral macrocycles via organocatalyzed enantioselective macrocyclization.

A novel enantioselective macrocyclization method has been developed for the asymmetric synthesis of planar-chiral macrocycles through chiral phosphoric acid-catalyzed intramolecular addition of the hydroxy group with the allenamide moiety. A series of planar-chiral macrocycles bearing various ring sizes (18-member to 22-member) and various functional groups were generated with good to high enantioselectivities.