Synthesis of thiosulfonates through aerobic oxidation of thiophenol under metal-free conditions

Thiosulfonate derivatives have shown a broad spectrum of biological activities and are used as powerful synthon in synthetic organic chemistry. As a consequence, oxidative reactions reactios of thiophenols have received colossal interest. Herein, a concise route for the synthesis of thiosulfonates has been disclosed through aerobic oxidation of thiophenol under metal -free reaction conditions. In this strategy, tetrabutylammonium iodide was used as a catalyst and tert-butyl nitrite with air were used as oxidants to construct a series of thiosulfonate derivatives (up to 86 % yield). This synthetic reaction could also be carried out at 5 mmol scale and the target product was obtained in 79 % yield. A series of control experiments and EPR characterization were carried out to demonstrate that the reaction went through a free radical process. A possible reaction mechanism was proposed.