A novel method for base‐promoted C3‐cyanoalkylation of oxindoles with readily available acrylonitrile derivatives has been achieved in the absence of light. Substrates bearing various substituents show good compatibility in an economical and redox‐neutral system. Mechanistic investigations unambiguously confirm a radical process mediated by an electron donor–acceptor (EDA) complex, formed from oxindole enolates associating with substituted acrylonitriles.
Wang et al. (Tue,) studied this question.