1: 90 percent / Na2S2O5 / H2O / a) below 40 deg C, 30 min, b) 0 deg C, 2 h 2: 68 percent / HCl(g) / 0 - 5 °C 3: 1.) NaH / 1.) THF, 2.) THF, reflux, 30 min 4: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, -78 deg C, 2 h View Scheme

1: 68 percent / HCl(g) / 0 - 5 °C 2: 1.) NaH / 1.) THF, 2.) THF, reflux, 30 min 3: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, -78 deg C, 2 h View Scheme

1: 1.) NaH / 1.) THF, 2.) THF, reflux, 30 min 2: 1.) n-BuLi / 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, -78 deg C, 2 h View Scheme

n-butyllithium 1.) THF, hexane, -78 deg C, 15 min, 2.) THF, hexane, -78 deg C, 2 h; Yield given. Multistep reaction;