Amide synthesis from alcohols and amines catalyzed by a RuII-N-heterocyclic carbene (NHC)-carbonyl complex

Treatment of [Ru-2(CO)(4)(CH3CN)(6)](BF4)(2) with 3-methyl-1-(pyridin-2-yl)-imidazolium bromide in the presence of tetrabutylammonium bromide at room temperature in dichloromethane affords a Ru-II-N-heterocyclic carbene-carbonyl complex [Ru(py-NHC)(CO)(2)Br-2] (1). Catalyst 1 displays diverse substrate scope for phosphine-free acceptorless coupling between alcohols and amines to amides at low catalyst loading. A Ru-II-dihydride/Ru-0 sequence is proposed in the catalytic cycle. (C) 2014 Elsevier B.V. All rights reserved.