α‐Trifluoromethyl Substituted α‐Hydroxyhydrazides as Dianionic Ligands Enable Cu‐Catalyzed Aryl Amination With Higher Turnovers

The α-trifluoromethyl-substituted α-hydroxy-hydrazides function as highly efficient ligands for copper-catalyzed coupling reactions between (hetero)aryl halides (Cl, Br) and amines. With (hetero)aryl chlorides, only 1 mol% of the catalyst is required to achieve complete conversion at 130°C. For (hetero)aryl bromides, the reaction proceeds efficiently at room temperature with just 0.5 mol% catalyst loading and can reach nearly 10,000 turnovers when heated to 90°C. These turnover numbers represent the highest reported to date for copper-catalyzed amination of (hetero)aryl halides (Cl, Br). The method is applicable to both primary and secondary amines, as well as a wide range of (hetero)aryl halides, delivering diverse (hetero)aryl amines in good to excellent yields.