1: 56 percent / acetonitrile / 6 h / 0 °C 2: 1.) n-BuLi, 2.) HMPA / 1.) THF, hexane, -78 deg C, 15 min, 2a.) THF, hexane, -78 deg C, 40 min, 2b.) -20 deg C, 30 min 3: 48 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 5 h / 25 °C 4: 68 percent / K2CO3 / methanol; H2O / 12 h / Ambient temperature View Scheme