Dinuclear Ni-2-Schiff base complex-catalyzed asymmetric 1,4-addition of beta-keto esters to nitroethylene toward gamma(2,2)-amino acid synthesis

A homodinuclear Ni-2-Schiff base 1 complex (1-10 mol%) promoted the catalytic asymmetric 1,4-addition reactions of beta-keto esters and an N-Boc oxindole to nitroethylene, giving products in 98-75% ee.