Catalytic redox-neutral carboxylation with CO₂

CO₂ is an attractive C1 building block for the construction of valuable chemicals from the standpoint of global sustainability. Recent years have witnessed the rapid development of diverse catalytic CO₂ fixations into organic compounds. Among various transformations, the synthesis of carboxylic acids with CO₂ through C-C bond formation is highly attractive due to the wide application of carboxylic acids in organic synthesis and industrial processes. The catalytic redox-neutral carboxylation of readily accessible starting materials with CO₂ leads to valuable carboxylic acids with high atom economy and selectivity. In this review, we summarize the development of redox-neutral carboxylation with CO₂ under different catalytic systems over the past two decades. The specifics are organized by the type of substrates reacting with CO₂, including catalytic carboxylation of C-X (X = Sn, B, Zn, Si) bonds, C-H bonds and unsaturated substrates. In addition, the remaining challenges and future avenues for investigation are also presented to guide continued exploration of this emerging field.