Enantioselective synthesis of 4,5-disubstituted pyrrolidin-2-one derivatives with two stereocenters on the basis of Michael adducts

The addition of malonates to trans-β-alkyl-β-nitrostyrenes in the presence of chiral Mg2+ bisoxazoline complex and Ni2+ and Co2+ bis((S,S)- or (R,R)-N,N′-dibenzylcyclohexane-1,2-diamine) complexes resulted in the formation of Michael adducts with two stereo-centers which were used as key precursors for the preparation of potentially biologically active enantiopure 4,5-disubstituted pyrrolidin-2-one derivatives.