Herein, a nickel catalysis system for desulfonylative C(sp2)–C(sp2) reductive cross-coupling reactions of aryl sulfone derivatives with a range of aryl bromides has been established to form diverse biaryl compounds. The complex Ar–Ni(II)–SO2CF3 bearing a phosphine ligand through oxidative addition of aryl sulfone to Ni(0) species was isolated and confirmed by an X-ray, which provides solid evidence for the understanding of the C(Ar)–SO2 bond activation and reaction mechanism.

Herein, we report an unprecedented cascade reaction of C­(sp2)–H addition to carbonyl and the C­(sp2)–CN/C­(sp2)–H coupling of 2-(2-oxo-2-arylethyl)­benzonitriles with indoles enabled by commercially available TsOH·H2O. The protocol represents the first metal-free C­(sp2)–CN/C­(sp2)–H coupling, affording a new route for the synthesis of various benzo­[a]­carbazole derivatives with a broad substrate scope, high yields, and simple conditions.

Herein, we report the first general C(sp 2 )−C(sp 2 ) reductive cross-coupling reaction of diverse triarylphosphines with a wide range of aryl halides by palladium/nickel co-catalysis. This protocol offers a unique route for the synthesis of biaryl compounds via the activation of inert C(Ar)−P bonds. The mechanistic studies demonstrate that the formation of the phosphonium salts in situ plays a key role in the catalytic cycle.