Photoinduced Site-Selective Functionalization of Aliphatic C-H Bonds by Pyridine N-oxide Based HAT Catalysts

Readily available and facilely tunable pyridine N-oxides have been developed as effective photoinduced hydrogen-atom-transfer (HAT) catalysts for site-selective C-H functionalizations of a broad range of C-H substrates, including unactivated alkanes. Pyridine N-oxide radicals, catalytically generated from Noxides by photoredox catalyzed single-electron oxidation, are the key intermediates that enable an effective HAT process for carbon radical generation to achieve alkylation, amination, azidation, allylation, and cyanation. Additionally, the fine-tuning of reactivity and selectivity of pyridine N-oxides through operationally simple structural modification was investigated and showed promising capability for selective functionalization of unactivated C(sp(3))-H bonds.

Automated summary

Readily available and facilely tunable pyridine N-oxides have been developed as effective photoinduced hydrogen-atom-transfer (HAT) catalysts for site-selective C-H functionalizations. The pyridine N-oxide radicals generated from Noxides by photoredox catalyzed single-electron oxidation are the key intermediates for achieving alkylation, amination, azidation, allylation, and cyanation. The fine-tuning of reactivity and selectivity through operational simple structural modification shows promising capability for selective functionalization of unactivated C(sp(3))-H bonds.