1.1: 79 percent / p-TsOH / toluene / 5 h / Heating 2.1: butyllithiun / tetrahydrofuran; hexane / 4 h / 25 °C 2.2: 71 percent / tetrahydrofuran / 15 h / 25 °C View Scheme

toluene-4-sulfonic acid in toluene Dehydration; 5 h; Heating;