A facile direct anti-selective catalytic asymmetric Mannich reaction of aldehydes with preformed N-Boc and N-Cbz imines.

Anti-selective Mannich reactions of N-Boc and N-Cbz protected imines with unmodified aldehydes proceeded smoothly under the catalysis of a secondary amine-thiourea catalyst, which led to high yields (70%-95%) and excellent enantioselectivity (up to 96 : 4 dr and >99% ee) under conventional organic synthetic operations.