Lipase-catalyzed acylation of 2-hydroxyiminomethyl-1,1'-binaphthyl [(+/-)-1] and hydrolysis of 2-acetoxyiminomethyl-1,1'-bitiaphthyl [(+/-)-2] yielded optically active oximes 1 and 2 with high enantiomeric excess. Successful synthesis of the optically active aldehyde 4 from chiral O-acetyl oxime 2 occurred without a decrease of enantiomeric excess. (C) 2003 Elsevier Ltd. All riahts reserved.