P ^III /P ^V ═O Redox Catalysis-Mediated Direct Thioesterification of Carboxylic Acids with Aryl Sulfinates

A direct and practical method for synthesizing thioesters via organophosphorus-catalyzed deoxygenative transformation of aryl sulfinates with carboxylic acids under an ambient atmosphere is presented. This protocol features a broad functional group tolerance and accommodates a wide range of sulfinates and carboxylic acids. The strategy is successfully applied to various hypervalent organosulfur substrates, including sulfinic acids, sulfonyl chlorides, and sodium sulfonates. Its synthetic utility is further demonstrated through the late-stage functionalization of pharmaceutical carboxylic acids and scalable gram-scale synthesis. Mechanistic studies provide strong evidence of a catalytic cycle involving a key proton-transfer event.