Palladium-catalyzed direct thiolation of aryl C-H bonds with disulfides

A catalytic variant of the direct thiolation of arenes, bearing directing groups, with disulfides or thiols has been developed under palladium and copper co-catalysis. Both sulfenyl moieties of the disulfide could be incorporated into the thiolated products, therefore, the reactions reached completion with only half an equivalent of disulfide, with respect to the starting arene. Experimental evidence suggested that the reaction proceeds through a Pd ^II/Pd^IV mechanism. A direct thiolation of unactivated aryl C-H bonds with disulfides or thiols is achieved under palladium catalysis (see scheme). The reaction allows the straightforward and chemoselective introduction of a thiolate group into arenes possessing directing groups. Mechanistic studies reveal that this reaction proceeds through a Pd^II/Pd ^IV mechanism.