bromine; acetic acid in dichloromethane T=0 - 20°C;

1: in tetrahydrofuran; hexane; acetonitrile T=0 - 20°C; 0.5 h; 2: With hydrogen bromide in tetrahydrofuran; hexane; water; acetonitrile T=0 - 20°C; 1 h;

1: (benzotriazo-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate; triethylamine / N,N-dimethyl-formamide / 16 h / 0 - 20 °C 2: tetrahydrofuran / 1 h / 0 - 20 °C 3: bromine; acetic acid / 1 h / 20 °C View Scheme

1: tetrahydrofuran / 1 h / 0 - 20 °C 2: bromine; acetic acid / 1 h / 20 °C View Scheme