Brønsted Base-Switched Selective Mono- and Dithiolation of Benzamides via Copper Catalysis

A versatile protocol
for the direct thiolation of an inert sp2 C–H bond
is presented via a catalytic amount of copper
catalysis, by switching related Brønsted bases and regulating
the reaction time, and the corresponding mono- and dithiolation products
can be obtained selectively in moderate to good yields. The reaction
exhibits a relatively broad substrate scope and a good functional
group tolerance, even with different heterocyclic amides and alkyl
thiols.