Photoredox catalyzed hydroazolylation of alkenes via phosphoranyl radicals

Abstract

Herein, a general protocol for the hydroazolylation of alkenes with N-hydroxyl azoles is reported. These reactions proceed via a phosphoranyl radical that is accessed by photoredox catalysis, followed by radical coupling of the resulting azole radical to the alkene radical. The key point of this reaction lies in the specific binding between the hydroxy group on N-hydroxyazole and alkyl phosphine. This specificity enables the reaction to overcome the selectivity issues associated with the existing hydroazolylation reactions, arising from the conjugation effects of different nitrogen atoms in azole substrates, leading to N₁/N₂/N₃ reaction site selectivity problems. Moreover, this protocol is also applicable to both intramolecular alkenes and external non-terminal alkenes.