1: (COCl)2, DMSO, Et3N / CH2Cl2 / 1 h / -78 °C 2: 90 percent / KF / 18-crown-6 / dimethylformamide / 3 h / 25 °C 3: p-TsOH*H2O / 3 h / 25 °C 4: NaBH4 / aq. ethanol / 2 h / 25 °C 5: 82 percent / 80percent aq. AcOH / 15 h / 80 °C 6: Pb(OAc)4 / benzene / 0.67 h / 25 °C 7: KF / 18-crown-6 / dimethylformamide / 3.5 h / 2 °C 8: Ac2O / p-TsOH*H2O / 1.5 h / 25 °C 9: 78 percent / KF / 18-crown-6 / tetrahydrofuran / 1 h / 2 °C 10: 28percent aq. NH4OH / aq. ethanol / 0.5 h / 25 °C 11: CSA / CH2Cl2 / 1 h / 25 °C 12: n-Bu3SnH, AIBN / toluene / 0.33 h / 110 °C 13: 10percent aq. AcOH / acetone / 14 h / 25 °C 14: 5percent NaOMe / methanol / 2 h / 25 °C 15: Na / liquid ammonia / 0.5 h / -78 °C View Scheme