Enantioselective and solvent-controlled diastereoselective Mannich reaction of isatin imines with hydroxyacetone: synthesis of 3-substituted 3-aminooxindoles.

The diastereoselectively switchable enantioselective Mannich reaction of isatin imines with hydroxyacetone is reported. The chiral primary amino acid catalyzed this Mannich reaction to afford both anti- and syn-Mannich adducts in high yields, good diastereoselectivities, and enantioselectivities. The reason for the solvent control of the diastereoselectivity phenomenon was investigated.