Next, we studied the substrate scope under the optimized reaction conditions (Figure ). First, the effect of aryl groups was investigated. Aldimine 2b, derived from benzaldehyde, gave corresponding adduct 4b with 85% ee by employing 1.3 equiv of 3a. Three-component synthesis starting from benzaldehyde, 3,4,5-trimethoxyaniline, and benzothiazoline 3a was also successful to afford 4b with almost same enantioselectivity (84% ee) albeit in moderate yield (62%). Meta-substituted aromatic imines were suitable substrates, affording the corresponding adducts with high enantioselectivities, and various meta-substituents were tolerated. A range of meta-substituents such as chloro, fluoro, methyl, methoxy, and tert-butyl groups were tolerated (4c-4g, 85-92% ee). Aldimine 2h bearing the m-nitrophenyl moiety gave adduct 4h with moderate enantioselectivity. The methoxycarbonyl group was tolerated and 4i was obtained with 81% ee. Ortho-substituted phenyl moieties were also suitable to give 4j and 4k in high yields and with slightly low enantioselectivities.