Visible Light-Promoted γ-C(sp3)-H Acylation of Aliphatic Amines Enabled by N-Heterocyclic Carbene Organocatalysis.

Abstract

The development of an environmentally benign protocol for the site-selective γ-C(sp3)-H acylation of aliphatic amines is of significant interest given their utility in accessing a diverse collection of γ-aminoketones prevalent in biologically active compounds. Herein, we report a visible-light-driven γ-C(sp3)-H acylation of aliphatic amines enabled by N-heterocyclic carbene (NHC) organocatalysis. This work demonstrates the generation of an aryl radical via single-electron transfer from the enolate form of an electron-rich Breslow intermediate to an aryl iodide under visible-light irradiation. This photoinduced aryl radical then facilitates a 1,7-hydrogen atom transfer (HAT) from the γ-C(sp3)-H bond to generate a more stable alkyl radical, which serves as the actual acylation site.