Acyl Radical Chemistry via Visible-Light Photoredox Catalysis

Visible-light photoredox catalysis enables easy access to acyl radicals under mild reaction conditions. Reactive acyl radicals, generated from various acyl precursors such as aldehydes, α-keto acids, 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 the recent progress on visible-light-driven acyl radical generation using transition-metal photoredox catalysts, metallaphotocatalysts, hypervalent iodine catalysts or organic photocatalysts. 1 Introduction 2 The Scope of This Review 3 Aldehydes as a Source of Acyl Radicals 4 α-Keto Acids as a Source of Acyl Radicals 5 Carboxylic Acids as a Source of Acyl Radicals 6 Anhydrides as a Source of Acyl Radicals 7 Acyl Thioesters as a Source of Acyl Radicals 8 Acyl Chlorides as a Source of Acyl Radicals 9 Acyl Silanes as a Source of Acyl Radicals 10 Conclusions and Future Outlook