Lewis Acid Promoted Diastereoselective Addition of TMSCN and TMSCF3 to Isatin-Derived N-Sulfinyl Ketimines: Synthesis of Optically Active Tetrasubstituted 3-Aminooxindoles
摘要:
A practical and efficient method for preparation of highly enantiomerically enriched 3-cyano-3-aminocaindoles and 3-trifluoromethyl-3-aminooxindoles with up to 99% optical purity by a Lewis acid promoted diastereoselective Strecker reaction and trifluoromethylation of isatin-derived N-tert-butanesulfinyl ketimines has been developed. This protocol allows direct use of N-free isatin substrates under mild conditions.