Metal- and solvent-free direct C-H thiolation of aromatic compounds with sulfonyl chlorides

A simple, efficient and green method for the direct thiolation of aromatic compounds using commercially available sulfonyl chlorides as the sulfur source was developed under metal- and solvent-free conditions. The C-S bond was constructed via direct C-H functionalization of diverse aromatic compounds under an oxygen atmosphere. In this process, various diaryl sulfides were synthesized in moderate to excellent yields. This protocol shows a broad substrate scope and good functional group tolerance. Moreover, a gram-scale experiment was also conducted to prove the prospect of this method for the scale-up synthesis of diaryl sulfides. Mechanistic studies indicate that this procedure probably undergoes a radical pathway.