Bismuth-mediated Direct Conversion of Aromatic Sulfonyl Chlorides into Thiosulfonate under Solvent-free Conditions

Abstract

When milled together with bismuth shots in the presence of pyridine, aromatic sulfonyl chlorides underwent facile reductive dehalogenation to give the corresponding arenethiosulfonates in moderate to good yield. Without pyridine, the reaction was quite reluctant to proceed. The composition and yield of the product are considerably dependent on the substituent group present on aromatic ring as well as the amount of pyridine employed. Electron-donation groups apparently facilitated the reaction to go further, leading to diaryl disulfides as the major product. Increased amount of pyridine also favored the formation of diaryl disulfides at the expense of arenethiosulfonates. Based on the results obtained, a possible reaction pathway has been presented.