A 1,2-Dicarbadodecaborane(12)-1,2-Dithiolate Chelating Ruthenium Carbene Catalyst for Highly Z Selective Olefin Metathesis

A highly Z selective olefin metathesis ruthenium carbene catalyst containing a 1,2-dicarbadodecaborane(12)-1,2-dithiolate ligand was synthesized, and the structure was determined by single-crystal X-ray diffraction. Due to the large steric hindrance and strong electron-withdrawing effects of the carborane ligand, the new ruthenium complex is more stable than previously reported Ru catalysts which contain benzene-1,2-dithiolate ligands. The new ruthenium carbene catalyst can catalyze cross-metathesis (CM) reactions of terminal alkenes with (Z)-but-2-ene-1,4-diol and CM reactions of other terminal alkenes to give highly Z selective products in moderate to good yields. In addition, the catalyst was also able to catalyst a ring-closing metathesis (RCM) reaction to give a macrocyclic ring compound with a (Z)-olefin structure as the major product. Like other ruthenium carbene catalysts, the new complex tolerates many different functional groups.