Photocatalytic carboxylation with CO2

Due to the structural characteristics of carbon dioxide (CO2) molecule, which has high thermodynamic stability and kinetic inertness, it is challenging to achieve efficient activation and selective conversion of CO2 under mild conditions. Since carboxylic acids do not only exist widely in natural products and bioactive drugs, but also serve as important bulk chemicals in industry, chemists have made great efforts to develop novel light-induced carboxylation employing CO2 in recent years. In this chapter, we will introduce the photocatalytic carboxylation of various substrates with CO2 to construct diverse carboxylic acids. This article is arranged based on the different types of reaction substrates with CO2, including carboxylation of C − H bonds, C −(pseudo)halide bonds, unsaturated substrates and miscellaneous. We highlight the mechanisms of these reactions, which can proceed in the presence of a photoredox catalyst or a photoredox/transition metal dual catalytic system. We also discuss a perspective on their prospects, hopefully stimulating the further research and development of this appealing field.