1: pyridine / CH2Cl2 / 0.25 h / -10 °C 2: 56 percent / NaN3 / pyridine / 120 h / Ambient temperature 3: 95 percent / TBAF / tetrahydrofuran / 2 h / Ambient temperature 4: 88 percent / pyridine / 5 h / Ambient temperature 5: 1,) conc. H2SO4, 2.) pyridine, DMAP / 1.) 4 deg C, 6 d, 2.) room temperature, overnight 6: 1.) MSTFA, 2.) TMS-OTf / 1.) DCE, reflux, 30 min, 2.) DCE, 80 deg C, overnight 7: 52 percent / NH3 / tetrahydrofuran / 60 °C 8: 97 percent / H2 / Pd/C / ethanol / 6 h / 760 Torr View Scheme

Multi-step reaction with 2 steps 1: 70 percent / H2SO4 / 3 h / Ambient temperature2: 60 percent / imidazole / pentane / 3 h / Ambient temperature  

With  pyridine in  dichloromethane 9 h;  Ambient temperature;