1: 1.) magnesium shavings, 1,2-dibromoethane / 1.) THF, reflux; 2.) THF, reflux, 1 h 2: 70 percent / Br2 / CHCl3; CCl4 3: 0.17 h / 100 °C View Scheme

magnesium; ethylene dibromide 1.) THF, reflux; 2.) THF, reflux, 1 h; Yield given. Multistep reaction;

1: 1.) Mg, 1,2-dibromoethane / 1.) THF, reflux; 2.) THF, reflux, 1 h 2: 89 percent / diethyl ether / 48 h View Scheme