Reductive Carboxylation of Unsaturated Hydrocarbons with Carbon Dioxide

Transition metal-catalyzed reductive carboxylation of unsaturated hydrocarbons with CO2 is a promising and potential strategy, offering an excellent alternative access to carboxylic acids/acrylic acids. The active transition metal species could react with unsaturated hydrocarbons and CO2 to generate the stable metallalactones or carboxylic salts. The transmetalation between reductants and metallalactones/carboxylic salts regenerates the active catalytic species. As a result, the reductive carboxylation is able to run in a catalytic mode rather than stoichiometric version. Organometal species, silanes/boranes, metal powder, methanol and hydrogens have been developed as reducing reagents in reductive carboxylation with CO2. In this perspective, the latest advances on the transition metal-catalyzed reductive carboxylation are summarized, with particular focus on the application of reductants and related reaction mechanism at a molecular level.