phosphorus tribromide in chloroform 2 h; Heating;

2: 76 percent / NaBH4 / ethanol / 1) r.t., 2 h, 2) reflux, 15 h 3: 79 percent / PBr3 / CHCl3 / 2 h / Heating View Scheme

1: 39 percent / anhydrous K2CO3 / dimethylsulfoxide / 6 h / 100 °C 2: 76 percent / NaBH4 / ethanol / 1) r.t., 2 h, 2) reflux, 15 h 3: 79 percent / PBr3 / CHCl3 / 2 h / Heating View Scheme