boron trichloride in dichloromethane 3.5 h; Ambient temperature;

1: 86 percent / BCl3 / CH2Cl2 / 3.5 h / Ambient temperature 2: 96 percent / BBr3 / CH2Cl2 / 27 h / Ambient temperature 3: 81 percent / Cu2O, 2,2'-bipyridyle / bis-(2-methoxy-ethyl) ether / 9 h / Heating View Scheme