Visible-light-induced radical-cascade alkylation/cyclization of acrylamides: access to 3,3-dialkylated oxindoles

Abstract

A visible-light-induced deoxygenative alkylation/cyclization of acrylamides with alcohols activated by CS₂ has been developed by using xanthate salts as alkyl radical precursors in the presence of tricyclohexylphosphine. It proceeds through a tandem radical addition/cyclization process, and this protocol provides a reliable and practical approach to building the skeleton of 3,3-disubstituted oxindoles in moderate to good yields. Notable features of this reaction include readily available starting reagents, broad substrate scope and mild reaction conditions.