Copper-catalyzed thiophenol C−H activation is described. Through an initial attempt to conduct C-arylation with arylboronic acid, a rather surprising sequential C−H activation and S-arylation was discovered. Mechanistic investigation revealed the disulfide intermediate as the key component in directing C−H oxidation. The overall reaction proceeded under mild conditions with molecular oxygen as the oxidant. Discovery of disulfide as the directing group provides a potential new direction for catalytic C−H functionalization under mild conditions.

An Rh-catalyzed selective C−H bond activation of diaryl-substituted anilides is described. In an attempt to achieve C−H activation of C-aryl rings, we unexpectedly obtained an N-aryl ring product under non-coordinating anion conditions, whereas the C-aryl ring product was obtained in the absence of a non-coordinating anion. This methodology has proved to be an excellent means of tuning and adjusting selective C−H bond activation of C-aryl and N-aryl rings. The approach has been rationalized by mechanistic studies and theoretical calculations. In addition, it has been found and verified that the catalytic activity of the rhodium catalyst is obviously improved by non-coordinating anions, which provides an efficient strategy for obtaining a highly chemoselective catalyst. Mechanistic experiments also unequivocally ruled out the possibility of a so-called “silver effect” in this transformation involving silver.

Transition-metal-catalyzed CF activation, in comparison with CH activation, is more difficult to achieve and therefore less fully understood, mainly because carbon–fluorine bonds are the strongest known single bonds to carbon and have been very difficult to cleave. Transition-metal complexes are often more effective at cleaving stronger bonds, such as C(sp²)X versus C(sp³)X. Here, the iridium-catalyzed CF activation of fluorarenes was achieved through the use of bis(pinacolato)diboron with the formation of the BF bond and self-coupling. This strategy provides a convenient method with which to convert fluoride aromatic compounds into symmetrical diaryl ether compounds. Moreover, the chemoselective products of the CF bond cleavage were obtained at high yields with the CBr and CCl bonds remaining.