Advances in photocatalytic carboxylation of C(sp3)–H bonds with CO2: a sustainable strategy for CO2 fixation

Carbon dioxide (CO₂) is well recognized as a sustainable C₁ synthon for producing a variety of carboxylic acid derivatives, including important natural and synthetic amino acids. In recent years, the inertness and high stability of the CO₂ molecule have been successfully overcome through various stoichiometric and catalytic methods. Among these, visible-light-induced photoredox catalysis has emerged as a popular and effective approach, offering a greener and more sustainable solution. Various carboxylation reactions involving C(sp3)–H, C(sp2)–H, C(sp)–H, and Ar–X have been successfully developed by using a suitable photocatalyst under visible light excitation. In this mini review, we explore recent progress in carboxylation reactions through the functionalization of C(sp3)–H bonds specifically in various organic molecules using molecular CO₂ through photocatalysis including organo-photocatalysts, homogeneous photocatalysts and heterogeneous photocatalysts along with their application in the development of bioactive molecules such as (±)-clopidogrel, (±)-tirofiban intermediate and DL-DOPA.