摘要:
Conjugate addition of a 50:50 pseudoenantiomeric mixture of lithium (R)-N-benzyl-N(alpha-methylbenzyl)amide and lithium (S)-N-3,4-dimethoxybenzyl-N-(alpha-methylbenzyl)amide to a range of racemic acyclic gamma-amino-alpha,beta-unsaturated esters (derived from the corresponding a-amino acids) effects their efficient parallel kinetic resolution, allowing the preparation of enantiopure beta,gamma-diamino esters. The beta,gamma-dlamlno ester products of these reactions are readily converted into the corresponding substituted 4-aminopyrrolidin-2-ones via N-debenzylation and cyclization.