1: 95 percent / Ph3P, imidazole iodine / tetrahydrofuran / 1 h / Ambient temperature 2: 100 percent / calcium carbonate / acetonitrile / 72 h / 50 °C 3: 1.) n-BuLi / 1) THF, hexane, -78 --> -40 deg C, 45 min; 2) THF, HMPA, hexane, -78 deg C --> rt, 90 min 4: 100 percent / aq. CF3CO2H / CH2Cl2 / 0.5 h / 0 °C 5: 1.) n-BuLi / 1) THF, hexane, -78 deg C --> rt; 2) THF, hexane, HMPA, -78 deg C --> rt, 60 min View Scheme