Chiral phosphine-catalyzed asymmetric [4 + 1] annulation of polar dienes with allylic derivatives: Enantioselective synthesis of substituted cyclopentenes

Abstract

A chiral phosphine-catalyzed asymmetric [4 + 1] annulation reaction of polar 1,3-dienes and allylic derivatives is reported. Under the catalysis of P-chiral bicyclic phosphine (15 mol%), a series of 1,1-dicyano-2,4-diaryl-1,3-dienes (21 examples) readily undergo stereoselective [4 + 1] annulation reactions with allylic acetate under mild conditions, delivering enantio-enriched polysubstituted cyclopentenes in 49–89% yields and 51–98% ee. A plausible mechanism for the reaction is also discussed.