Electrochemical synthesis of γ-keto sulfones containing a β-quaternary carbon center via 1,2-migration

Abstract

An effective electrochemical rearrangement reaction, both oxidant and metal catalyst-free, is presented to construct γ-keto sulfones containing a β-quaternary carbon center in this study. In the protocol, radicals are generated from benzenesulfonyl hydrazines, which cause 1,2-migrations of starting materials, 2-methylallyl alcohol derivatives, and formation of new C–C and C–S bonds. A series of aryl-migration, alkyl-migration and ring expansion products are obtained in good yields with excellent functional group tolerance. Gram-scale reaction demonstrates that the electro-oxidative rearrangement strategy has the potential for industrial practicability. Additionally, a possible and reasonable mechanism is proposed based on existing literature reports, control experiments and cyclic voltammograms.