Enantioselective\nMannich\nReaction between Cyclic <i>N</i>‑Sulfonyl Ketimines\nand Isatin-Derived Ketimines

An\nenantioselective Mannich reaction with cyclic <i>N</i>-sulfonyl\nketimines as the nucleophiles was developed. In the presence\nof 5 mol % chiral thiourea catalyst <b>C11</b>, the asymmetric\nMannich reaction between cyclic <i>N</i>-sulfonyl ketimines\nand isatin-derived ketimines was achieved in high yields and good-to-excellent\nenantioselectivities (84–99% yields with 75–99.8% ee).\nThis methodology provided an effective route to construct chiral 3-amino-2-oxindoles\ncontaining a cyclic <i>N</i>-sulfonyl ketimine scaffold.\nThe initial biological evaluation of the products in cell-based assays\ndemonstrated that some compounds have excellent antiproliferative\nactivity against human osteosarcoma cells.