dibromotriphenyl-phosphorane in acetonitrile 1.) 60-70 deg C, 1 h, 2.) 350 deg C, 1 h;

1: concd. HCl / ethanol / 24 h / Heating 2: 73 percent / (Ph)3PBr2 / acetonitrile / 1.) 60-70 deg C, 1 h, 2.) 350 deg C, 1 h View Scheme

1: 1.) n-BuLi / 1.) Et2O, -78 deg C, 1 h, 2.) Et2O, -78 deg C, 1 h 2: concd. HCl / ethanol / 24 h / Heating 3: 73 percent / (Ph)3PBr2 / acetonitrile / 1.) 60-70 deg C, 1 h, 2.) 350 deg C, 1 h View Scheme

bromine; iron(III) chloride; iron in tetrachloromethane