Photoinduced Co/Ni-cocatalyzed Markovnikov hydroarylation of unactivated olefins with aryl bromides.

Transition-metal-catalyzed hydroarylation of unactivated alkenes metal hydride hydrogen atom transfer (MHAT) is an attractive approach for the construction of C(sp)-C(sp) bonds. However, this kind of reaction focuses mainly on using reductive hydrosilane as a hydrogen donor. Here, a novel photoinduced Co/Ni-cocatalyzed Markovnikov hydroarylation of unactivated alkenes with aryl bromides using protons as a hydrogen source has been developed. This reaction represents the first example of photoinduced MHAT a reductive route intercepting an organometallic coreactant. The key to this transformation was that the Co-H species was generated from the protonation of the Co intermediate, and the formed Co-C(sp) intermediate interacted with the organometallic coreactant rather than reacting with nucleophiles, a method which has been well developed in photoinduced Co-catalyzed MHAT reactions. This reaction is characterized by its high catalytic efficiency, construction of quaternary carbons, simple reaction conditions and expansion of the reactive mode of Co-catalyzed MHAT reactions a reductive route. Moreover, this catalytic system could also be applied to complex substrates derived from glycosides.