1: 95 percent / NBS / CCl4 / 1.5 h / Heating 2: 80 percent / CuBr / pyridine / 14 h / Ambient temperature; addition at -30 deg C 3: TsOH / toluene / 20 h 4: H2O, 0.5n HCl / ethanol / Ambient temperature 5: alkali View Scheme

1: 95 percent / NBS / CCl4 / 1.5 h / Heating 2: 80 percent / CuBr / pyridine / 14 h / Ambient temperature; addition at -30 deg C 3: TsOH / toluene / 20 h 4: H2O, 0.5n HCl / ethanol / Ambient temperature View Scheme