Direct C(sp3)–H Cross Coupling Enabled by Catalytic Generation of Chlorine Radicals
Published in Journal of the American Chemical Society, 2016
Recommended citation: Shields, Benjamin J.; Doyle, Abigail G. “Direct C(sp3)–H Cross Coupling Enabled by Catalytic Generation of Chlorine Radicals” J. Am. Chem. Soc., 2016, 138, 12719–12722. https://pubs.acs.org/doi/full/10.1021/jacs.6b08397?src=recsys
Here we report the development of a C(sp3)–H cross-coupling platform enabled by the catalytic generation of chlorine radicals by nickel and photoredox catalysis. Aryl chlorides serve as both cross-coupling partners and the chlorine radical source for the α-oxy C(sp3)–H arylation of cyclic and acyclic ethers. Mechanistic studies suggest that photolysis of a Ni(III) aryl chloride intermediate, generated by photoredox-mediated single-electron oxidation, leads to elimination of a chlorine radical in what amounts to the sequential capture of two photons. Arylations of a benzylic C(sp3)–H bond of toluene and a completely unactivated C(sp3)–H bond of cyclohexane demonstrate the broad implications of this manifold for accomplishing numerous C(sp3)–H bond functionalizations under exceptionally mild conditions.