Rational design of *N*-heterocyclic compound classes via regenerative cyclization of diamines

The discovery of reactions is a central topic in chemistry and especially interesting if access to compound classes, which have not yet been synthesized, is permitted. N-Heterocyclic compounds are very important due to their numerous applications in life and material science. We introduce here a consecutive three-component reaction, classes of N-heterocyclic compounds, and the associated synthesis concept (regenerative cyclisation). Our reaction starts with a diamine, which reacts with an amino alcohol via dehydrogenation, condensation, and cyclisation to form a new pair of amines that undergoes ring closure with an aldehyde, carbonyldiimidazole, or a dehydrogenated amino alcohol. Hydrogen is liberated in the first reaction step and the dehydrogenation catalyst used is based on manganese.

Robin Fertig, Felix Leowsky-Künstler, Torsten Irrgang, Rhett Kempe