Ruthenium-catalyzed reduction of N-alkoxy- and N-hydroxyamides

A ruthenium-catalyzed reduction of N-alkoxy- and N-hydroxyamides was found to afford corresponding amides in good to high yields. A simple RuCl3/Zn–Cu/alcohol system, without the addition of any other ligands, exhibited a high catalytic activity, and therefore the present reaction does not require a stoichiometric amount of metals or metal complexes as reductants. When β-substituted-α,β-unsaturated N-methoxyamides were employed as substrates, concurrent hydrogenation of the olefin moiety proceeded slowly with deprotection of the methoxy group. In the reduction of N-hydroxyamides, the alcoholic solvent was found to function as a hydrogen donor.

Graphical abstractA ruthenium-catalyzed reduction of N-alkoxy- and N-hydroxyamides was found to afford corresponding amides in good to high yields. A simple RuCl3/Zn–Cu/alcohol system, without the addition of ligands, exhibited a high catalytic activity. The present reaction does not require a stoichiometric amount of metals or metal complexes as reductants.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We developed a Ru-catalyzed reduction of N-alkoxy- and N-hydroxyamides to amides. ► A RuCl3/Zn–Cu/alcohol system without ligands exhibits a high catalytic activity. ► A stoichiometric amount of metals or metal complexes is not required. ► The alcoholic solvent functions as a hydrogen donor.