1: 97 percent 2: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) r.t., 1 h 3: 53 percent / sodium hydroxide / aq. ethanol / 1 h / 80 °C View Scheme

iodine in dichloromethane T=20°C; 3 h;

1: 97 percent 2: 1.) n-BuLi / 1.) THF, -78 deg C, 2.) r.t., 1 h 3: 56 percent / sodium iodide / hexamethylphosphoric acid triamide / 1 h / 160 - 180 °C View Scheme