Generation of Carbon Dioxide Radical Anion from Formate Salts and its Use in Photochemical Reactions

Carbon dioxide radical anion (CO2 center dot-) is a reactive intermediate that can act as a powerful single electron reductant as well as a nucleophilic C1 radical source. However, its utility has not been well explored due to the fact that direct reductive approaches to access CO(2)(center dot- )from thermodynamically stable CO2 require deeply reducing conditions. This review focuses on a recently developed approach for the generation of CO2 center dot- via hydrogen-atom transfer under practical and mild conditions, which has enabled a variety of transformations that are difficult to achieve by conventional methods.