Asymmetric synthesis of tetrasubstituted cyclic amines via aza-Henry reaction using cinchona alkaloid sulfonamide/zinc(II) catalysts.

The first enantioselective aza-Henry reaction of non-activated cyclic iminoesters, derived from cyclic amino acids, has been developed. Good yields and enantioselectivities were observed for the reaction using our original cinchona alkaloid sulfonamide/zinc(II) catalyst. The transition state was proposed to explain the stereoselectivity based on experiments and DFT calculations.