Photoinduced Aryl Ketone-Catalyzed Phenylation of C(sp3)–H Bonds Attached to the Heteroatom of Ethers and N-Boc-amines via Concerted Homolytic Aromatic Substitution

A single-step phenylation at the non-acidic C(sp3)–H bond attached to the heteroatom of ethers and N-Boc-amines has been achieved using photoexcited 4-benzoylpyridine as a hydrogen atom transfer (HAT) catalyst. The design of electron-deficient (trifluoromethylsulfonyl)benzene derivatives, as a phenyl precursor, was critical to realizing the present transformation. Moreover, the DFT calculation indicated that the present transformation proceeds via a concerted homolytic aromatic substitution rather than via a stepwise one involving the formation of a cyclohexadienyl radical intermediate.