Stereoselective one-pot construction of N-substituted 3-alkylideneoxindoles through Pd(II)-catalyzed direct addition of aromatic C-H to alkyne and Heck reaction sequence

Abstract

3-Alkylideneoxindole derivatives, which constitute the core structural framework of current pharmaceuticals, are widely present as bioactive components in numerous natural molecules. Herein, a palladium-catalyzed cascade synthetic method for the construction of 3-alkylideneoxindole has been developed, and the reaction sequence comprises aryl C-H activation/intramolecular carbopalladation/Heck cross-coupling. Utilizing Pd(OAc)2 as the catalyst, AgOAc as the oxidant, and Mg(OAc)2 as the additive, a variety of N-alkyl or N-aryl anilides underwent reaction with alkenes in acetonitrile at 70 ℃ for 24 h to provide the corresponding (E)-3-alkylideneoxindole products with specific regio- and stereroselectivity in moderate to good yields.