1: 75 percent / NaH / 1,2-dimethoxy-ethane / 1.) r.t., 20 min, 2.) 65 deg C, 18 h 2: 96 percent / 66percent aq. dichloroacetic acid / 3 h / 9 °C 3: 82 percent / PPh3, I2, imidazole / toluene; acetonitrile / 0.5 h / 65 °C 4: 68 percent / aq. ammonium cerium(IV) nitrate / acetonitrile / 3 h / Ambient temperature View Scheme