Ruthenium-catalyzed acceptorless dehydrogenation of heterocycles

Highly efficient, selective ruthenium-catalyzed acceptorless dehydrogenation of heterocycles is reported. A simple and readily accessible dinuclear monohydrido bridged ruthenium complex [{(eta(6)-p-cymene)RuCl}(2)(mu-H-mu-Cl)] 1 is employed as a catalyst. The proposed reaction mechanism for dehydrogenation of N-heterocycles begins with N-H activation by the metal center; subsequent C-H activation and isomerization lead to the liberation of molecular hydrogen and formation of N-heteroarenes. Overall, this protocol can have applications in developing hydrogen storage strategies, biomass valorization, and atom-economical synthesis of heteroarenes.