1.1: 94 percent / 1,8-diazabicyclo[5.4.0]undec-7-ene / tetrahydrofuran / 1 h / cooling 2.1: trifluoroacetic acid / methanol / 0 - 20 °C 2.2: 85 percent / triethylamine; 4-(dimethylamino)pyridine / tetrahydrofuran / 3 h / 0 °C 3.1: 97 percent / (1,3-dimesitylimidazolidin-2-yl)(P(c-Hex)3)(Cl)2Ru=CHC6H5 / CH2Cl2 / 16 h / Heating 4.1: 76 percent / cerium(III) chloride heptahydrate; sodium borohydride / methanol / 3 h / 0 °C View Scheme