bromine; potassium carbonate; triphenylphosphine in N,N-dimethyl-formamide T=0°C; 1 h;

1: 92 percent / NaBH4 / methanol / 2 h / Ambient temperature 2: 69 percent / PhP3, K2CO3, Br2 / dimethylformamide / 1 h / 0 °C View Scheme

1: 66 percent / BF3*Et2O / 0.33 h / 40 °C 2: 92 percent / NaBH4 / methanol / 2 h / Ambient temperature 3: 69 percent / PhP3, K2CO3, Br2 / dimethylformamide / 1 h / 0 °C View Scheme