1: PDC, Ac2O / CH2Cl2 / 4 h / Heating 2: NaBH4 / methanol / 3 h / -20 °C 3: CF3CO2H / Heating 4: HCl / 2 h / Ambient temperature 5: pyridine / 1.) room temperature, 8 h, 2.) 45 deg C, 1.5 h 6: AcOH, H2SO4 / 0 °C View Scheme

1: PDC, Ac2O / CH2Cl2 / 4 h / Heating 2: NaBH4 / methanol / 3 h / -20 °C 3: CF3CO2H / Heating 4: HCl / 2 h / Ambient temperature 5: pyridine / 1.) room temperature, 8 h, 2.) 45 deg C, 1.5 h 6: AcOH, H2SO4 / 0 °C View Scheme

1: PDC, Ac2O / CH2Cl2 / 4 h / Heating 2: NaBH4 / methanol / 3 h / -20 °C 3: CF3CO2H / Heating 4: HCl / 2 h / Ambient temperature 5: pyridine / 1.) room temperature, 8 h, 2.) 45 deg C, 1.5 h 6: AcOH, H2SO4 / 0 °C 7: 1.) HCl gas, AcCl, 2.) H2O / 1.) CH2Cl2, 0 deg C, 12 h, 2.) MeCN, 0 deg C, 30 min View Scheme

1: PDC, Ac2O / CH2Cl2 / 4 h / Heating 2: NaBH4 / methanol / 3 h / -20 °C 3: CF3CO2H / Heating 4: HCl / 2 h / Ambient temperature 5: pyridine / 1.) room temperature, 8 h, 2.) 45 deg C, 1.5 h 6: AcOH, H2SO4 / 0 °C 7: 1.) HCl gas, AcCl, 2.) H2O / 1.) CH2Cl2, 0 deg C, 12 h, 2.) MeCN, 0 deg C, 30 min 8: 1.) SO2Cl2 / 1.) CH2Cl2, DMF, room temperature, 3 h, 2.) room temperature, 20 h 9: 1.) Et3N*3HF, 2.) Et3N / 1.) EtOAc, 80 deg C, 3 h, 2.) 80 deg C, 1 h View Scheme

1: pyridine / Ambient temperature 2: 94 percent / aq. HOAc / 1 h / 70 °C 3: 1.) BF3*OEt2, 4A MS, 2.) 2,6-lutidine / 1.) CH2Cl2, -60 deg C, 30 min, 2.) CH2Cl2, -20 deg C, 1 h 4: 50 percent / H2, Et3N / Pd/C / ethyl acetate; ethanol / 72 h / 50 °C / 38000 Torr 5: 65 percent / DBU / CH2Cl2 / 6 h / Ambient temperature 6: 69 percent / 4A MS, TMSOTf / CH2Cl2 / 0.33 h / -20 °C 7: 79 percent / Pd(MeCN)2Cl2 / acetone; H2O / Ambient temperature View Scheme