Sulfonamide-Derived N,N,N-Ligand Enabled Copper-Catalyzed Radical 1,2-Trichloromethylthioesterification of Styrenes

Abstract

The copper-catalyzed radical difunctionalization of alkenes using readily accessible carbon tetrachloride (CCl₄) and potassium benzothioate offers an attractive approach for thioester synthesis. Major challenges stem from the weak reducing capacity of copper catalysts in their ground state and the facile atom transfer radical addition between CCl₄ and alkenes. In this work, we describe an efficient radical 1,2-trichloromethylthioesterification of styrenes conducted under mild thermal conditions. The effectiveness of this approach depends on the application of an anionic sulfonamide-derived N,N,N-ligand, which not only boosts the reducing capability of the copper catalyst to initiate the reaction but also promotes the formation of C(sp³)–S bonds. This method exhibits a broad substrate scope, thus serving as a valuable complement to existing 1,2-carbothiolation of alkenes. Mechanistic investigations confirm that a radical mechanism is operative.