carbon tetrabromide; triphenylphosphine in acetonitrile T=25°C; 1 h;

1: 70 percent / Br2, NaOAc, HOAc / 2 h / 25 °C 2: 80 percent / NaH / dimethylformamide / 18 h / 25 °C 3: 86 percent / 5 N NaOH / benzene / 12 h / 25 °C 4: 1.) (Sia)2BH, 2.) H2O2, NaOH / 1.) THF, 0 deg C, 1 h, 2.) THF, 0 deg C, 1 h 5: 93 percent / TsOH / methanol / 4 h / 25 °C 6: 92 percent / CBr4, (C6H5)3P / acetonitrile / 1 h / 25 °C View Scheme

1: 80 percent / NaH / dimethylformamide / 18 h / 25 °C 2: 86 percent / 5 N NaOH / benzene / 12 h / 25 °C 3: 1.) (Sia)2BH, 2.) H2O2, NaOH / 1.) THF, 0 deg C, 1 h, 2.) THF, 0 deg C, 1 h 4: 93 percent / TsOH / methanol / 4 h / 25 °C 5: 92 percent / CBr4, (C6H5)3P / acetonitrile / 1 h / 25 °C View Scheme

1: 93 percent / TsOH / methanol / 4 h / 25 °C 2: 92 percent / CBr4, (C6H5)3P / acetonitrile / 1 h / 25 °C View Scheme

1: 86 percent / 5 N NaOH / benzene / 12 h / 25 °C 2: 1.) (Sia)2BH, 2.) H2O2, NaOH / 1.) THF, 0 deg C, 1 h, 2.) THF, 0 deg C, 1 h 3: 93 percent / TsOH / methanol / 4 h / 25 °C 4: 92 percent / CBr4, (C6H5)3P / acetonitrile / 1 h / 25 °C View Scheme