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.