in dichloromethane (η5-C5Me5)Ru(CO)2(CH2OMe) and Me3SiOSO2CF3 (1 equiv) in presence of twofold excess of styrene (Ar, CH2Cl2, -80°C); evapn. (room temp.), washing (ether), recrystn. (CH2Cl2/ether, -20°C);