carbon tetrabromide; triphenylphosphine in diethyl ether T=25°C; 0.5 h;

1: 1) n-BuLi / 1) Et2O, hexane, 0 deg C to room temperature; reflux, 24 h, 2) Et2O, hexane, -78 deg C to room temperature; room temperature, 2 h 2: 112.6 g / 10percent H2SO4 / diethyl ether; hexane 3: 95 percent / PBr3 / diethyl ether / 2 h / Ambient temperature View Scheme

1: 80 percent / various solvent(s) / 5.5 h / 80 - 100 °C 2: 1) n-BuLi, 2) HMPA / 1) THF, hexane, -78 deg C to room temperature, 2) THF, hexane, -78 deg C 3: 1) n-BuLi / 1) THF, hexane, -78 deg C to room temperature, 2) THF, hexane, -78 deg C to room temperature 4: TBAF, ethyl acrylate / acetonitrile / 0.83 h View Scheme