Synthesis of Spirooxindoles from N-Arylamide Derivatives via Oxidative C(sp2)–C(sp3) Bond Formation Mediated by PhI(OMe)2 Generated in Situ

A class of novel spirooxindole compounds (2) were readily synthesized, in a metal-free environment, from N-arylamide derivatives (1) via intramolecular oxidative cyclization. Direct oxidative C(sp²)-C(sp³) bond formation was realized with the least-studied PhI(OMe)₂ as an oxidant, formed in situ from the reaction between PhIO and MeOH.