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

Five different fluorinated beta-diketone ligands in the presence of sodium methoxide easily react with the organoruthenium precursor [(eta(6)-p-cymene)Ru(mu-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.