solvent yields methyl (R)-4-succinoyloxy-5-tetradecynoate with over 90% e.e.. Furthermore, this optically active diester was converted to (R)-5-(1-decynyl)oxacyclopentan-2-one by lipase-catalyzed enantioselective lactonization which enhanced its e.e. over 99%. The Japanesebeetlepheromone (R,Z)-(-)-5-(1-decenyl)oxacyclopentan-2-one is synthesized in one step from this optically active lactone.