Nitrogen ligand influence on the CO-assisted ruthenium-catalyzed reductive amination

A representative set of amines and N-heterocycles was applied as additives in the CO-assisted Ru-catalyzed reductive amination of p-anisaldehyde with p-anisidine. Among the tested ligands, pyridine caused a strong activation for low active aliphatic substrates while bidentate heterocyclic ligands possess significant inhibition of catalyst for the majority of substrates.