Enantioselective Mannich Reaction between Cyclic N -Sulfonyl Ketimines and Isatin-Derived Ketimines.

An enantioselective Mannich reaction with cyclic N -sulfonyl ketimines as the nucleophiles was developed. In the presence of 5 mol % chiral thiourea catalyst C11 , the asymmetric Mannich reaction between cyclic N -sulfonyl ketimines and isatin-derived ketimines was achieved in high yields and good-to-excellent enantioselectivities (84-99% yields with 75-99.8% ee). This methodology provided an effective route to construct chiral 3-amino-2-oxindoles containing a cyclic N -sulfonyl ketimine scaffold. The initial biological evaluation of the products in cell-based assays demonstrated that some compounds have excellent antiproliferative activity against human osteosarcoma cells.