1: 6.5 g / aq. acetic acid / 2 h / Heating 2: 4.3 g / 3percent KOH / methanol / 2.5 h 3: 3.7 g / pyridinium tosylate / tetrahydrofuran / 24 h / Ambient temperature 4: n-BuLi / tetrahydrofuran; hexane / 1 h / Heating 5: 270 mg / n-BuLi / tetrahydrofuran; hexane / 2 h / Ambient temperature 6: pyridinium tosylate / methanol / 20 h / Ambient temperature 7: cyclohexanone, aluminium isopropoxide / toluene / 0.5 h / Heating View Scheme