1: 2 h / 55 °C 2: Jones reagent 3: 1.) THF, -20 deg C, 30 min, 2.) DME, -20 deg C, 15 min 4: THF, -78 deg C, 30 min 5: Et3N / CH2Cl2 / 0.5 h / -5 °C 6: DBU / benzene / 25 °C 7: 81 percent / hydrogen, pyridine / Pd/C 8: ethanol / 7 h / 25 °C 9: LDA / tetrahydrofuran / -78 - 0 °C 10: Li,liquid NH3 11: 97 percent 12: 63 percent / KOH / ethanol / 16 h / 25 °C 13: pyridine / 8 h / 0 °C 14: 86 percent / DBU / pyridine / 3 h / 115 °C 15: aq. AcOH / tetrahydrofuran 16: 60 percent / PCC / CH2Cl2 / 2 h / 25 °C 17: 68 percent / NaH, n-BuLi / tetrahydrofuran / 0.25 h / 0 °C 18: 63 percent / Zn(BH4)2 / hexane / 1 h / 0 °C 19: p-TsOH*H2O / benzene / 0.5 h / 25 °C View Scheme