Homogeneous Catalysis for the Conversion of CO₂, CO, CH₃OH, and CH₄ to C₂₊ Chemicals via C–C Bond Formation

In the past few decades, the advances of CO2 reduction have been mostly focused on the synthesis of C1 products, such as CO, formic acid, methanol, and methane. However, the syntheses of C2+ products from generally abundant C1 sources such as CO2, CO, and CH4 are traditionally more difficult because they involve two selective processes: activation of the C1 source and simultaneous C–C bond formation. Recent advances in organometallic chemistry and catalysis provide effective means for the chemical transformation of C1 sources to higher-energy C2+ products under mild conditions. Moreover, the recent expansion of these mechanistically different methods has enabled the use of various C1 sources to undergo either homocoupling or heterocoupling via C–C bond formation to generate various C2+ products. In this review, we systematically present the various advances in C1 to C2+ conversions under homogeneous catalysis.