This article focuses on the substituent effect on the reactivity and selectivity of the ring-opening direction in the reaction of five-membered cyclic carbonates with n-hexylamine. The reactivity of the cyclic carbonate and the formation selectivity of the adduct with a secondary hydroxyl group increased as a stronger electron-withdrawing group was introduced at the a-methylene of the cyclic carbonate. These results are discussed on the basis of the stability of intermediates, primary and secondary alcoholate anions, Mulliken charges on carbonyl carbon, and the bond lengths and orders of the O-C=O single bond.