C(sp 2 )-C(sp 2 ) Reductive Cross-Coupling of Triarylphosphines with Aryl Halides by Palladium/Nickel Co-catalysis.

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.