Direct asymmetric anti-Mannich-type reactions catalyzed by cinchona alkaloid derivatives.

A series of cinchona alkaloid derivatives were used to catalyze the asymmetric anti-Mannich-type reaction of 3-methyl-2-oxindole with N-tosyl aryl aldimines. The resulting anti-3,3-disubstituted 2-oxindole products were obtained in good yields (up to 92%) with high diastereo- and enantioselectivities (anti/syn up to 97:3 and 91% ee).