Candida antarctica lipase B (Novozyme) is an effective catalyst for the dynamic kinetic resolution of racemic 2-benzyl-4-substituted-5(4H)-oxazolones, in the presence of an alcohol, yielding optically active N-benzoyl amino acid esters. The reaction has been optimised with respect to the solvent and the effect of a catalytic amount of organic base is investigated. (C) 2000 Elsevier Science Ltd. All rights reserved.