Carica papaya lipase-catalyzed transesterification of the 2, 2, 2-trifluoroethyl esters of N- benzyloxycarbonylated dl-amino acids carrying aliphatic side chains proceeded smoothly and, in almost all the cases, enantiospecifically (E=> 200), affording the l-methyl esters and leaving the d-trifluoroethyl esters intact.
