Synthesis of Catechol Thioethers through Gallic Acid/Fe2(SO4)3 Catalyzed Aerobic Oxidative Coupling of Thiols and Catechol Derivatives

Abstract A newly developed cooperative catalytic system Galic acid/Fe 2 (SO 4 ) 3 was employed in the syntheses of catechol thioethers through the direct aerobic oxidative coupling of various thiols with catechol derivatives. As the first organocatalytic oxidative method to prepare catechol thioethers except the enzymatical cases, it exhibits good tolerance and selectivity, leading to the good products in up to 95 % yields. It was postulated to undergo the divergent Michael‐type nucleophilic conjugate addition (1,4‐type or 1,6‐type) of the thiols onto the in‐situ generated ortho ‐benzoquinones.