toluene-4-sulfonic acid in benzene Dehydration; Heating;

Multi-step reaction with 2 steps 1.1: butyllithium; diisopropylamine / hexane; tetrahydrofuran / -78 - -20 °C1.2: 80 percent / tetrahydrofuran / -78 - 20 °C2.1: 74 percent / chromium(II) chloride; nickel cloride / dimethylformamide