Organocatalytic asymmetric Michael addition of benzofuran-2(3H)-ones to alkylideneindolenines generated in situ from arenesulfonylalkylindoles

An efficient enantioselective Michael addition of benzofuran-2(3H)-ones to alkylideneindolenines generated in situ from arenesulfonylalkylindoles has been described, and a series of optically active C-3 alkyl-substituted benzofuran-2(3H)-one derivatives containing indole skeleton with two adjacent stereocenters have been obtained. The resulting adduct can readily be converted to chiral o-hydroxyphenylacetic acid derivative with indole motif. (C) 2015 Elsevier Ltd. All rights reserved.