bromine in dichloromethane T=0°C; 0.5 h;

1: 1.) n-BuLi / 1.) hexane, THF, RT, overnight, 2.) THF, reflux, 1 h 2: 89 percent / 85percent phosphoric acid / 2 h / Heating 3: 65 percent / bromine / CH2Cl2 / 0.5 h / 0 °C View Scheme

1: 1.) n-BuLi / 1.) hexane, THF, RT, overnight, 2.) THF, reflux, 1 h 2: 89 percent / 85percent phosphoric acid / 2 h / Heating 3: 65 percent / bromine / CH2Cl2 / 0.5 h / 0 °C View Scheme

1: 89 percent / 85percent phosphoric acid / 2 h / Heating 2: 65 percent / bromine / CH2Cl2 / 0.5 h / 0 °C View Scheme