Metal‐Free Electrochemical Synthesis of Sulfonamides Directly from (Hetero)arenes, SO ₂, and Amines

Abstract

Sulfonamides are among the most important chemical motifs in pharmaceuticals and agrochemicals. However, there is no methodology to directly introduce the sulfonamide group to a non‐prefunctionalized aromatic compound. Herein, we present the first dehydrogenative electrochemical sulfonamide synthesis protocol by exploiting the inherent reactivity of (hetero)arenes in a highly convergent reaction with SO ₂ and amines via amidosulfinate intermediate. The amidosulfinate serves a dual role as reactant and supporting electrolyte. Direct anodic oxidation of the aromatic compound triggers the reaction, followed by nucleophilic attack of the amidosulfinate. Boron‐doped diamond (BDD) electrodes and a HFIP–MeCN solvent mixture enable selective formation of the sulfonamides. In total, 36 examples are demonstrated with yields up to 85 %.

Abstract

A convergent single‐step synthesis of sulfonamides directly from (hetero)arenes, SO ₂, and amines by electrochemical C−H activation is presented. No prefunctionalization of the aromatic compound is required and halogen substituents are tolerated. The in situ formation of the amidosulfinate species serves a dual role as nucleophile and supporting electrolyte.