Transition metal-catalyzed carboxylation of olefins with Carbon dioxide: a comprehensive review

Carbon dioxide (CO2) utilization for the production of fuels and energy-rich chemicals is one of the attractive topics of research in modern-day chemistry. The main barriers in the CO2 utilization include: 1) the cost associated in CO2 capture, separation, purification, and transportation; 2) higher energy demand for conversion due to its higher kinetic and thermodynamic stability; 3) the lack of socio-economical driving forces. Valorization of CO2 has been realized as a viable option for the mitigation of CO2 as well as to create new business opportunities. Carbon dioxide is a nontoxic, renewable, and abundant C1 source; whereas carboxylation of olefins to carboxylic acids represents one of the most important transformations owing to the broad applicability of these chemicals in various domains, such as water-absorbing polymers, preservatives of food, fertilizers, building blocks for the manufacturing of cosmetics, soaps, detergents, rubbers, dyes, animal feed, plastics, agrochemicals and pharmaceuticals. The present review mainly focuses on the recent advances in the transition metal-catalyzed carboxylation of the olefins by using carbon dioxide as a feedstock. Firstly, the hydrocarboxylation or direct carboxylation using coordination complexes of transition metals such as rhodium, copper, cobalt, nickel, ruthenium, iron, palladium, and zirconium have been discussed in detail. In the next section, the hetero carboxylation reactions, for example, boracarboxylation, silacarboxylation, carbocarboxylation, thiocarboxylation and dicarboxylation have been presented to explore the wider scope of CO2 utilization for carboxylation reactions. Lastly, the carboxylation of dienes and difunctionalization reactions have been discussed. Further, the recent trends and key challenges in the use of CO2 as a carbxylating agent for carboxylation reactions have been described.