ASYMMETRIC CYCLOADDITION OF N-METALATED AZOMETHINE YLIDES WITH THE OPTICALLY-ACTIVE ALPHA,BETA-UNSATURATED ESTERS DERIVED FROM ALPHA-AMINO-ACIDS

α,β-Unsaturated esters bearing a chiral oxazolidine or perhydropyrrolo[1,2-c]imidazole auxiliary at the β-position have been prepared and applied to the cycloadditions with N-metalated azomethine ylides derived from a-(benzylideneamino) esters. These reactions are found to proceed with an exclusively high diastereofacial selectivity to give 2,4-pyrrolidinedicarboxylates with four consecutive chiral centers after the removal of chiral auxiliary. Detailed stereochemistry in the transition state is discussed. © 1990 The Chemical Society of Japan.