A Strategy for Amide C-N Bond Activation with Ruthenium Catalyst: Selective Aromatic Acylation.

A strategy for amide C-N bond activation with ruthenium catalyst is described for the first time. The in situ formed bis-cycloruthenated complexes were demonstrated to be the key active species with superior oxidative addition ability to an inert amide C-N bond. The direct C-H bond activation of 2-arylpyridines followed by the amide C-N bond activation took place in the presence of a ruthenium precatalyst to produce monoacylation products in moderate to good yields. Synthetically useful functional groups, such as halogen atoms (F and Cl), ester, acetyl, and vinyl, remained intact during tandem C-H/C-N bond activation reactions.