1: 50 percent / t-BuOH / tetrahydrofuran / 15 h / 20 °C 2: 89 percent / benzene / 6 h / Heating 3: 18 percent / diethyl ether / 15 h / 20 °C View Scheme

tert-butyl alcohol in tetrahydrofuran T=20°C; 15 h;