Sustainable catalysis by Mn: Amide Synthesis from Alcohols and generation of H2 as energy source

Density functional theory calculations unveil the mechanism of the original example of a base-metal-catalyzed synthesis of amides from alcohols and amines, generating H₂ as a subproduct. Instead of a convoluted mechanism with the implication of dissociation of some ligand of the manganese catalyst, our DFT calculations describe a facile protocol, where the catalyst only produces aldehydes from alcohols. Once formaldehyde is formed from methanol, it reacts with the amine to form a second alcohol that undergoes the same procedure as methanol and creates the desired amide through a double-carrousel mechanism. This reaction is eminently sustainable in different ways: it uses alcohols and generates molecular hydrogen, without releasing CO₂, but the interesting formation of amides. In addition, to speed up the process the reaction has a manganese catalyst, with manganese being one of the most abundant metals in the Earth’s layer.

A. Luque-Urrutia, T. Pèlachs, M. Solà, A. Poater; “Double-Carrousel Mechanism for Mn-Catalyzed Dehydrogenative Amide Synthesis from Alcohols”; ACS Catal. 2021, DOI: 10.1021/acscatal.1c00693