Enantioselective aza-Diels-Alder reaction catalyzed by a chiral Bronsted acid: Effect of the additive on the enantioselectivity

Danishefsky's diene and aldimine underwent aza Diels-Alder reaction under the influence of chiral phosphoric;acid derived from (R)-BINOL as a chiral Bronsted acid to afford piperidinone derivatives in good to high enantioselectivity. Addition of CH,CO,H improved both reactivity and enantioselectivity.