1: NaHCO3 / H2O; tetrahydrofuran / 0.5 h 2: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C, 30 min, 2.) THF, hexane, -78 deg C, 30 min View Scheme

1: NaHCO3 / H2O; tetrahydrofuran / 0.5 h 2: 1.) n-butyllithium / 1.) THF, hexane, -78 deg C, 30 min, 2.) THF, hexane, -78 deg C, 30 min 3: 99 percent / Et3N / CH2Cl2 / 2 h / Ambient temperature 4: 96 percent / NaN3 / dimethylformamide / 5 h / 65 °C 5: tetrahydrofuran / 2 h 6: H2O / 10 h / 40 °C 7: pyridine / CH2Cl2 / Ambient temperature View Scheme