Mechanistic Insights into La-Catalyzed Amidation of Aldehyde with Amine.

A new mechanism of La-catalyzed amidation of N-methylbenzylamine with p-chlorobenzaldehyde has been computationally proposed, where L2La[NR1R2] (I) rather than previously proposed L2La[OCHRNR1R2] (II) is the catalytically active species. Interestingly, the side-product alcohol acting as a proton relay to reduce reaction energy barrier could participate in the regeneration of I. Besides, DFT calculations suggest that an addition of alcohol additive into the initial reaction system could accelerate the reaction, which has been further verified by experiments.