Advances of photocatalytic carboxylation of C(sp3)-H bond with CO2: A sustainable strategy for CO2 fixation

Abstract

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. Despite its sustainability, the CO2 molecule's high thermodynamic stability and kinetic inertness pose significant challenges to its broader application in organic synthesis. 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, 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 using photocatalysis including organo-photocatalysts, homogeneous photocatalysts and heterogeneous photocatalysts.