Novel Organoruthenium(II) β-Diketonates as Catalysts for Ortho Arylation via C–H Activation

Abstract

Five different fluorinated β-diketone ligands in the presence of sodium methoxide easily react with the organoruthenium precursor [(η 6 - p -cymene)Ru(μ-Cl)Cl] 2, generating neutral complexes 1 – 5 with typical “piano-stool” geometry. All synthesized compounds were characterized by multinuclear NMR, X-ray diffraction, and other standard physicochemical methods. These isolated organoruthenium(II) complexes are air-, moisture-, and UV-stable compounds and were tested for catalytic activity. It was found that these compounds are ready to use catalysts, which are efficient for direct arylation of 2-phenylpyridine. With the use of 4-bromoacetophenone as arylating reagent, these complexes show enhanced selectivity for monoarylated products. All reagents are commercially available and relatively inexpensive, which makes these catalysts generally available.