 Also, Pi stacking between the aryl group and aldehyde was suggested as an organizational feature which imparted high enantioselectivity to the cycloaddition.Yamamoto and co-workers have introduced a conceptually interesting series of catalysts that incorporate an acidic proton into the active catalyst.This kind of what so called Bronsted acid-assisted chiral Lewis acid (BLA) catalyzes a number of diene-aldehyde cycloaddition reactions.