Lipase from Candida cylindracea catalyzes regioselective interesterification between an acyl donor and a terminal diol. Discrimination between primary hydroxyl groups in a dissymmetric molecule has not been previously described. Preparation of (R)-2-thiobenzyl-4-acetoxy-hydroxybutane 4 obtained in this way, allows the assignement of the (R) absolute configuration to 2-thiobenzyl-1,4-butandiol derivatives previously obtained in a yeast transformation.