Visible light photoredox catalysis has enabled easy access to acyl radicals under mild reaction conditions. Reactive acyl radicals, generated from various acyl precursors such as aldehydes, α-ketoacids, carboxylic acids, anhydrides, acyl thioesters, acyl chlorides, or acyl silanes, can undergo a diverse range of synthetically useful transformations, which were previously difficult or inaccessible. This review summarizes such recent progress of visible-light-driven acyl radical generation using transition metal photoredox catalysts, metallaphotocatalysts, hypervalent iodine catalysts or organic photocatalysts.
Keywords: Acyl Radical; Acylation; Cross-Coupling; Oxidation; Photoredox Catalysis; Reduction; Single Electron Transfer; Visible-Light.