A chloro-bridged (arene)Ru complex with a polymerizable side chain
An [(arene)RuCl2](2) complex with a methacrylate side chain (2) has been prepared in two steps using commercially available starting materials. This complex reacts with PPh3, pyridine, or toluidine to give the corresponding mononuclear adducts (3-5). The structure of 4 was determined by single-crystal X-ray diffraction. Complex 2 and the PPh3 adduct 3 were immobilized by copolymerization with divinylbenzene (DVB) or ethyleneglycol dimethacrylate (EGDMA). The resulting EGDMA copolymer was tested as a catalyst in asymmetric transfer hydrogenations. Using (1R,2R)-(-)-N-p-tosyl-1,2-diphenylethylenediamine as the chiral ligand and azeotropic NEt3/HCO2H as the reducing agent, aromatic ketones were converted to the corresponding alcohols with selectivities between 87 and 97% ee.