A new route to optically active, unsymmetrical cis-cyclohexene-1,2-dicarboxylate derivatives has been developed on the basis of the asymmetric Diels-Alder reaction of chiral, unsymmetrical maleates catalyzed by certain Lewis acids. A notably high level of asymmetric induction has been observed in the asymmetric Diels-Alder reaction of unsymmetrical maleates possessing chiral auxiliaries such as alpha-phenethyl and trans-2-phenylcyclohexyl groups. The origin of the chiral outcome using these dienophiles has been elucidated.