On the Immobilization of Ruthenium Metathesis Catalysts in Imidazolium Ionic Liquids

New ionophilic Hoveyda-type complexes were prepared by the treatment of Grubbs' second-generation catalyst with the readily obtained 2,3-dimethyl-1-[1-methyl-3-(2-vinylphenoxy)butyl]imidazolium hexafluorophosphate ligand, for example. This new carbene complex immobilized in BMI·PF6 ionic liquid presents excellent catalytic activities in 1,7-octadiene, diallyl diethylmalonate, and allylmethallyl dimethylmalonate ring-closing metathesis (RCM) reactions. The ionophilic complex can be recycled up to seven times in the 1,7-octadiene RCM reaction. The structure of this complex has been unambiguously established by NMR and single-crystal X-ray diffraction studies.