Tetramethylammonium Iodide (TMAI)‐Promoted Sulfenylation/Annulation of Enaminones with Thiosulfonates

A highly efficient and eco‐friendly method for the tetramethylammonium iodide‐mediated sulfenylation/annulation of enaminones using thiosulfonates as the sulfenyl source was described under open‐air, metal‐, and oxidant‐free conditions. This method provides an alternative way of constructing C−S bonds, affords various substituted sulfenylated chromones in moderate to good yields, and shows broad substrate scope, and good functional group tolerance. Tetramethylammonium iodide (TMAI)‐promoted sulfenylation/annulation of enaminones using widely accessible thiosulfonates as the sulfenyl source was described under metal‐ and oxidant‐free conditions. These methods provide an alternative and facile synthetic route to access a series of 3‐sulfenylated chromones in moderate to good yields. This is a useful, time‐efficient, and scalable procedure for the construction of C(sp2)−S bonds.