Catalytic O₂ activation toward oxidative N-S bond formation by a thiolato Fe(III) complex

Compounds with the benzisothiazol-3-one (BIT) skeleton perform excellently in the pharmaceutical field, although current synthetic methods remain limited in terms of synthetic efficiency. Herein, we report the catalytic intramolecular N-S bond formation for BITs from easily prepared disulfide precursors by an Fe(III) dithiolate through O₂ activation at 298 K. Interestingly, the catalytic performance is enhanced by substituting O₂ with a milder O-donor oxidant, ONMe₃. Catalytic oxygenation of PPh₃ to OPPh₃ can also proceed under similar conditions. In addition, the first anionic monosulfenato Fe(III) species, Fe(III)-S(O)R, is isolated with structural characterization from the reaction of Fe(III) thiolate and ONMe₃.