1: 80 percent / ZnCl2 / diethyl ether / 1 h / 25 °C 2: 83 percent / triphenylphosphine, diethyl azodicarboxylate / tetrahydrofuran / 1.5 h / 25 °C 3: 93.5 percent / KOH / methanol; H2O; tetrahydrofuran / 2 h / 25 °C View Scheme

zinc(II) chloride in diethyl ether T=25°C; 1 h;