Direct asymmetric aza Diels–Alder reaction catalyzed by chiral 2-pyrrolidinecarboxylic acid ionic liquid

The utility of [EMIm][Pro] as an efficient catalyst for the one-pot direct asymmetric aza Diels–Alder reaction has been developed. A set of cyclic α,β-unsaturated ketones have been explored in up to 93% yield with up to >99/1 dr and >99% ee. Moreover, the catalytic system can be recycled and reused for six times without any significant loss of catalytic activity.