1: CCl4; methanol / 6 h / 0 °C 2: 1.) NaH / 1.) THF, -10 deg C, 10 min, 2.) RT, 24 h 3: tetrahydrofuran / 48 h / Ambient temperature 4: 64 percent / 6 N HCl / acetic acid / 3 h / 100 °C View Scheme