Organic Photoredox Catalyzed Direct Hydroamination of Ynamides with Azoles

Abstract

Disclosed herein is a photoinduced selective hydroamination of ynamides with nitrogen heteroaromatic nucleophiles. By using an organocatalytic photoredox system, a direct method to construct a diverse of (Z)-α-azole enamides from ynamides and pyrazoles, as well as triazoles, benzotriazoles, indazoles, and tetrazoles, is developed, thus providing a photocatalytically synthetic route to heterocyclic motifs common in medicinal agents. Based on the mechanistic studies, the hydroamination is postulated to operate via a mechanism in which the single-electron oxidation of ynamide and the intermediacy of an alkyne radical cation, is responsible for the observed reactivity.