1: 67 percent / N-bromosuccinimide, PPh3 / CH2Cl2 / 0.5 h / Ambient temperature 2: 76 percent / KOH, tetrabutylammonium iodide / CH2Cl2 / 16 h / Ambient temperature 3: 65 percent / 45percent HBr / 0.5 h / Heating View Scheme

1: 70 percent / thionyl chloride / benzene / 24 h / Heating 2: 1.) NaH / 1.) EtOH, 10 min, 2.) EtOH, reflux, 24 h 3: 93 percent / 48percent HBr / 5 h / 130 - 140 °C View Scheme

thionyl chloride 0.416667 h; Heating;

1: 67 percent / Ph3P, NBS / CH2Cl2 / 0.5 h / Ambient temperature 2: 1.) BuLi / 1.) THF, hexane, -70 deg C, 10 min, 2.) THF, hexane, -70 deg C, 5 h 3: 70 percent / 0.25 N aq. HCl / 3 h / Ambient temperature 4: 47 percent / 48percent aq. HBr / 0.25 h / Heating View Scheme