Efficient and chemoselective imine synthesis catalyzed by a well-defined PN³-manganese(ii) pincer system

The highly efficient reductive amination of aldehydes with ammonia (NH₃) and hydrogen (H₂) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN³-manganese(ii) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH₃ as a nitrogen source under H₂ in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes.