Pyridine N-oxides as HAT reagents for photochemical C-H functionalization of electron-deficient heteroarenes

Pyridine N-oxides have only recently marked their presence in the photocatalysis field, mainly serving as oxypyridinium salt precursors. Herein, their unique reactivity as a hydrogen atom transfer reagent in photochemical, Minisci-type alkylation of electron-deficient heteroarenes is unveiled. The formation of an EDA complex between a heterocyclic substrate and N-oxide precludes the need for a photocatalyst. The developed method allows for a broad range of radical precursors to be used, namely alkanes, alkenes, amides, and ethers, for efficient alkylation of azines.

Automated summary

Pyridine N-oxides have been recently discovered as effective reagents in the photocatalysis field, serving as precursors for oxypyridinium salts and hydrogen atom transfer in alkylation reactions of electron-deficient heteroarenes. This method eliminates the need for a photocatalyst and allows for efficient alkylation of a broad range of azines using various radical precursors.