Pyridine N-oxides as HAT reagents for photochemical C-H functionalization of electron-deficient heteroarenes
Łukasz W Ciszewski1, Dorota Gryko1
1Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland. dorota.gryko@icho.edu.pl.
Abstract:
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.
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