Catalytic Asymmetric Alkylation of 3-Aryl-Substituted Oxindoles to give 3,3-Disubstituted Oxindoles under Phase-Transfer Conditions

摘要

An efficient enantioselective method for the construction of all-carbon quaternary stereocenters from 3-aryl-substituted oxindoles via asymmetric phase-transfer alkylation has been developed. The products are obtained in high yields and optical purity of up to 93% ee by using (5',5')-3,4,5-trifluorophenyl-NAS bromide as a chiral phase-transfer catalyst. The 3,3-disubstituted oxindole products are valuable intermediates for the synthesis of bioactive indole-containing natural products.