Asymmetric [3 + 2] cycloaddition of donor–acceptor cyclopropanes with azadienes enabled by Brønsted base catalysis

A chiral bifunctional Brønsted base-catalyzed enantioselective [3 + 2] cycloaddition of D–A cyclopropanes and azadienes is reported. The protocol features broad substrate scope, mild reaction conditions and high functional group tolerance.