Cooperative NHC/Photoredox Catalysis: Three Component Radical Coupling of Aroyl Fluorides, Styrenes and Alcohols

Cooperative NHC/photoredox catalysis has emerged as an important research field in recent years. Herein, the use of tertiary alcohols as alkyl radical precursors to perform three component radical coupling with styrenes and aroyl fluorides for the preparation of alpha-arylated alkyl aryl ketones is described. Reaction of an aroyl fluoride with the NHC catalyst provides an acyl azolium ion that can be reduced by the photoredox catalyst to the corresponding ketyl radical anion. Oxidatively generated C-radicals derived from the alcohol add to the styrene derivative and subsequent cross coupling of the adduct radical with the ketyl radical delivers after NHC fragmentation the targeted ketone.

Automated summary

Cooperative NHC/photoredox catalysis is an important research field. Tertiary alcohols are used as alkyl radical precursors to perform three component radical coupling, leading to the synthesis of alpha-arylated alkyl aryl ketones. The reaction involves the formation of an acyl azolium ion from an aroyl fluoride with the NHC catalyst, which is then reduced by the photoredox catalyst to generate a ketyl radical anion. The generated C-radicals derived from the alcohol add to the styrene derivative and undergo cross coupling with the ketyl radical, resulting in the targeted ketone after NHC fragmentation.