A Highly Selective Manganese-Catalyzed Synthesis of Imines under Phosphine-Free Conditions

An efficient and highly selective phosphine-free NN-manganese­(I)
complex catalyst system was developed for the acceptorless dehydrogenative
coupling of alcohols with amines to form imines. The coupling reactions
underwent at 3 mol % catalyst loading, and a large range of alcohols
and amines with diverse functional groups was applied, including challenging
diol and diamine. The target imine products were obtained in good
to excellent yields. The present work provides an alternative method
to construct highly active nonprecious metal complex catalysts based
on phosphine-free ligands.