Dual Nickel(II)/Mechanoredox Catalysis: Mechanical‐Force‐Driven Aryl‐Amination Reactions Using Ball Milling and Piezoelectric Materials

Abstract The combination of a nickel(II) catalyst and a mechanoredox catalyst under ball‐milling conditions promotes mechanical‐force‐driven C−N cross‐coupling reactions. In this nickel(II)/mechanoredox cocatalyst system, the modulation of the oxidation state of the nickel center, induced by piezoelectricity, is used to facilitate a highly efficient aryl‐amination reaction, which is characterized by a broad substrate scope, an inexpensive combination of catalysts (NiBr 2 and BaTiO 3 ), short reaction times, and an almost negligible quantity of solvents. Moreover, this reaction can be readily up‐scaled to the multi‐gram scale, and all synthetic operations can be carried out under atmospheric conditions without the need for complicated reaction setups. Furthermore, this force‐induced system is suitable for excitation‐energy‐accepting molecules and poorly soluble polyaromatic substrates that are incompatible with solution‐based nickel(II)/photoredox cocatalysts.