1: 80percent AcOH / 4 h / 90 °C 2: pyridine / 72 h / Ambient temperature 3: 1.) N,O-bis(trimethylsilyl)acetamide, 2.) TMS-triflate / 1.) CH3CN, room temperature, 1 h, 2.) 60 deg C, 2 h 4: 95 percent / NaOMe / methanol / 0.17 h / Ambient temperature 5: 1.) pTsCl, 2.) NaH / 1.) CH2Cl2, Py, -10 deg C, 3 h, 2.) DMF, 0 deg C, 12 h 6: 78 percent / H2 / Pd(OH)2/C / ethanol / 4 h View Scheme

1: 80percent AcOH / 4 h / 90 °C 2: pyridine / 72 h / Ambient temperature 3: 1.) N,O-bis(trimethylsilyl)acetamide, 2.) TMS-triflate / 1.) CH3CN, reflux, 1 h, 2.) 65 deg C, 2 h 4: 97 percent / NaOMe / methanol / 0.17 h / Ambient temperature 5: 1.) pTsCl, 2.) NaH / 1.) Py, room temperature, 20 h, 2.) DMF, 0 deg C, 72 h 6: 98 percent / H2 / Pd(OH)2/C / ethanol / 4 h / Ambient temperature View Scheme