The phosgenation reactions of dibutyl amine 1i and the cyclic amines 1j and 1k achieved 99, 83, and 58% yields, respectively. The proline derivative 1l also afforded the desired product in a moderate yield. The benzyl-substituted amine 1m and the tetrahydroisoquinoline derivatives 1n and 1o were well tolerated under the reaction conditions, and provided the desired products in excellent yields.