Cu(triNHC)‐Catalyzed N‐Methylation and N‐Formylation of Amines Using CO₂

To address carbon emissions and promote sustainable chemical use, the development of carbon‐utilizing protocols is essential. In this context, leveraging CO 2 as a methyl group precursor holds significant potential for broadening its scope in organic reactions. Aiming to reduce the carbon footprint in organic synthesis, we introduce an efficient and selective Cu(triNHC) (triNHC = tri‐ N ‐Heterocyclic Carbene) catalyst designed for the reduction of CO 2 and subsequent N ‐methylation and N ‐formylation of amines. The triNHC ligand's tridentate chelation is crucial for modulating Cu(triNHC)’s reactivity. This configuration enables direct N ‐methylation of amines, bypassing the typical N ‐formylation and subsequent reduction pathway. As a result, N ‐methylation proceeds faster than in reactions catalyzed by copper catalysts with simpler NHC ligand coordination. Our mechanistic investigations provide support for the proposed reaction pathway, involving CO 2 reduction to a methyl precursor followed by its reaction with amines.