An Efficient Heterobimetallic Lanthanide Alkoxide Catalyst for Transamidation of Amides under Solvent-Free Conditions

A practical heterobimetallic lanthanide-catalyzed transamidation of primary, secondary and tertiary amides with aliphatic and aromatic amines has been developed. The methodology was also applied to the weakly reactive thioamides to demonstrate its versatility and wide substrate scope. The heterobimetallic lanthanide catalysts showed high catalytic activity and a wide scope of substrates with good to excellent yields under solvent-free conditions. Efficient activation of the transamidation can be realized by the above complexes acting as cooperative acid-base bifunctional catalysts, which are proposed to be responsible for the higher reactivity in comparison with simple monometallic catalysts.