1: 96 percent / Br2 / CH2Cl2; CHCl3 / 0.67 h / -70 °C 2: 42 percent / 1,4-diazabicyclo<4.3.0>non-5-ene / diethyl ether / 3 h / Ambient temperature View Scheme

bromine in dichloromethane; chloroform T=-70°C; 0.666667 h;