Natural gallic acid catalyzed aerobic oxidative coupling with the assistance of MnCO3 for synthesis of disulfanes in water†
The formation of S–S bonds has great significance and value in synthetic chemistry and bioscience. To pursue a sustainable approach for such a synthesis, an aerobic oxidative coupling method for the efficient preparation of organic disulfanes, using a low-toxic natural gallic acid as an organocatalyst, inexpensive MnCO3 as a cocatalyst, O2 as the terminal oxidant and water as the solvent, has been successfully developed. Such metal–organic cooperative catalytic protocol provided an access to various symmetrical and unsymmetrical disulfanes in up to 99% yield. Gram scale synthesis with practical convenience and low loading of catalysts further illustrates the practicability of our method.