thallium ethylate in chloroform T=60°C;

1: 2.) Br2 / 1.) tetrachloroethylene, diglyme, 130 deg C, 30 min, 2.) CCl4, 4 h 2: 1.) tri-n-butyltin hydride, azobis(isobutyronitrile), 2.) NaOH / 1.) 130 deg C, 108 h, 2.) H2O, reflux, 2 h View Scheme

1: 2.) Br2 / 1.) tetrachloroethylene, diglyme, 130 deg C, 30 min, 2.) CCl4, 4 h 2: 1.) tri-n-butyltin hydride, azobis(isobutyronitrile), 2.) NaOH / 1.) 130 deg C, 108 h, 2.) H2O, reflux, 2 h 3: 51 percent / diethyl ether / 4 h / Ambient temperature View Scheme