1: 86 percent / Cuprous bromide, ammonium bromide, copper powder / HBr / 1.5 h / 0 °C 2: 1.) n-butyllithium; 2.) 1,2-diiodoethane / 1.) Ether, hexane, -78 deg C, 30 min; 2.) 0 deg C, 1 h; Room temperature, 10 minute View Scheme

(i) Me2CuLi, Et2O, (ii) I2, 1,2-dimethoxy-ethane; Multistep reaction;

n-butyllithium; 1,2-di-iodoethane 1.) Ether, hexane, -78 deg C, 30 min; 2.) 0 deg C, 1 h; Room temperature, 10 minute; Yield given. Multistep reaction;