disodium hydrogenphosphate; sodium amalgam in tetrahydrofuran; methanol 24 h; Ambient temperature;

Multi-step reaction with 2 steps 1: tetra-n-butylammonium fluoride / tetrahydrofuran / -78 °C2: 1.) n-BuLi; 2.) C2Br2Cl4 / 1.) THF, -78 deg C, 15 min  

With  n-butyllithium; C2Br2Cl4  1.) THF, -78 deg C, 15 min;  Yield given. Multistep reaction;