Radical-Mediated Tandem Functional Group Transfer, Desulfonylation, and Cyclization Reactions: Synthesis of Oxindoles

Abstract

Desulfonylative skeletal editing has emerged as a powerful strategy in modern organic synthesis; however, desulfonylation of sulfonamides remains underdeveloped. Furthermore, the integration of radical cascades with Truce–Smiles rearrangement for simultaneous skeleton construction and remote functional-group migration is rare. To address these challenges, we developed a visible-light photoredox-catalyzed desulfurization strategy that combines radical cyclization relay, Truce–Smiles rearrangement, and desulfurization-driven rearomatization to access oxindoles efficiently. The reaction proceeds through a radical 1,4-cyano migration-triggered cyclization/desulfurization cascade under mild conditions using readily available, bench-stable substrates. Notably, the protocol is not restricted to alkyl bromodifluoroacetates and is compatible with a broad range of bromoesters.