1: 56 percent / LiI*2H2O, 2,4,6-collidine / 19 h / Heating 2: 1.) O3; 2.) NaBH4 / methanol; 1.) -50 deg C, 0.25 h; 2.) -30 deg C, 1 h 3: pyridine / 18 h / Ambient temperature 4: 81 percent / CrO3 / pyridine; CH2Cl2 / 1.5 h / Ambient temperature 5: 1.) 1.6 M n-BuLi / 1.) Et2O, room temp., 3 h; 2.) THF, reflux, 4 h 6: 71 percent / Na, liq. NH3 / tetrahydrofuran / 0.5 h 7: 75 percent / pyridine / 48 h / -20 °C 8: 90 percent / dibenzo-18-crown-6 / acetonitrile / a) room temp., 1 h; b) reflux, 18 h 9: tetrahydrofuran 10: 68 percent / 1 N HCl / Heating View Scheme