Acid‐Cooperative Transition Metal‐Catalysed Oxygen‐Atom‐Transfer: Ruthenium‐Catalysed C−H Oxygenation

Abstract

AbstractThe prospect of developing methods to control the reactivity of metal(oxo) holds appeal for both synthetic and bioinorganic chemistry. In this study, we observed that carboxylic acids enhance reactivity in C−H oxidation by forming hydrogen bonds with the oxo ligand, thereby increasing the basicity and electrophilicity of the oxo intermediate. Additionally, we discovered that H‐dicarboxylate ligands, such as oxalate, malonate, and maleate, significantly improve the catalyst turnover frequency (up to 760/h) in unactivated C(sp3)−H oxidation. Furthermore, the addition of maleic acid was also found to activate Fe and Mn(pdp)‐catalysed C−H oxygenation. Notably, Ru(bpga)(H‐maleate)2 3‐catalyzed C−H functionalization exhibited a broad functional group tolerance, including bromine, hydroxyl, benzoate, nitro, nitryl, sulfonate, imide, sulfonylamide, and carbamate, yielding up to 98% in a site‐ and chemoselective manner with only 0.1–2.0 mmol% loading.