1: 63 percent / t-BuOK / 2-methyl-propan-2-ol / 8 h 2: NaOMe, TiCl3, aq. CH3COONH4 / methanol; tetrahydrofuran / 1 h 3: pyridine / tetrahydrofuran / 3.5 h 4: t-BuOK / benzene; 2-methyl-propan-2-ol / 2 h / Ambient temperature 5: 6 M HCl, glac. AcOH, O2 / 5 h / Heating View Scheme