Efficient and chemoselective imine synthesis catalyzed by a well-defined PN-manganese(II) pincer system.

The highly efficient reductive amination of aldehydes with ammonia (NH) and hydrogen (H) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN-manganese(II) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH as a nitrogen source under H 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.