1: 95 percent / NBS / 110 - 115 °C 2: 74 percent / anhydr. ZnBr2 / xylene / 8 h / Heating 3: 5.7 g / n-butyl-lithium, diisopropylamide / tetrahydrofuran; hexamethylphosphoric acid triamide; hexane / 0.33 h / -78 °C 4: 94 percent / tetrahydrofuran / -78 deg C, 1 h, 20 deg C, 1 h 5: 83 percent / benzene sulphonyl chloride / CH2Cl2 / 24 h / Ambient temperature View Scheme

N-bromosuccinmide T=110 - 115°C;

potassium tert-butylate in DMF (N,N-dimethyl-formamide) T=20°C; 72 h;

ammonium chloride

1: 95 percent / NBS / 110 - 115 °C 2: 74 percent / anhydr. ZnBr2 / xylene / 8 h / Heating View Scheme

1: 95 percent / NBS / 110 - 115 °C 2: 74 percent / anhydr. ZnBr2 / xylene / 8 h / Heating 3: 5.7 g / n-butyl-lithium, diisopropylamide / tetrahydrofuran; hexamethylphosphoric acid triamide; hexane / 0.33 h / -78 °C 4: 70 percent / tetrahydrofuran; H2O / 2 h / Ambient temperature 5: 75 percent / methanesulphonyl chloride / pyridine / 20 h / Ambient temperature View Scheme

1: 95 percent / NBS / 110 - 115 °C 2: 74 percent / anhydr. ZnBr2 / xylene / 8 h / Heating 3: 5.7 g / n-butyl-lithium, diisopropylamide / tetrahydrofuran; hexamethylphosphoric acid triamide; hexane / 0.33 h / -78 °C 4: 94 percent / tetrahydrofuran / -78 deg C, 1 h, 20 deg C, 1 h 5: 93 percent / zinc bromide / CH2Cl2 / -95 deg C 1 h, RT., 2 day View Scheme

sodium hydride in tetrahydrofuran T=0°C; 10 h;