biocatalytic approach has been designed for the synthesis of optically active piperazinones and 1,4-diazepanones in aqueousmedium under mild conditions. The method described herein is based on a biocatalytic transamination of an easily accessible N-(2-oxopropyl) aminoacid ester and the subsequent spontaneous cyclization of the initially formed amine. Both enantiomers of the synthesized piperazinones