1: Et3N / CH2Cl2 / 0.5 h 2: 56 percent / Ag2CO3 / acetone; H2O / 27 h / Heating 3: 82 percent / 2,6-lutidine / CH2Cl2 / 3.25 h / -50 - 0 °C 4: BuLi / diethyl ether / 1.) -80 to -30 deg C, 1.5 h, 2.) -60 deg C to r.t., 5 h 5: H2SO4, H2O / tetrahydrofuran / 0.42 h / Ambient temperature 6: HF, I2, H2O / acetonitrile / 48 h / Ambient temperature 7: 82 percent / 2,6-lutidine / CH2Cl2 8: 14 percent / CeCl3*7H2O, NaBH4 / methanol / 1.67 h / -60 - 0 °C 9: DMAP, pyridine / CH2Cl2 / 12 h / Ambient temperature 10: pyridine*HF / tetrahydrofuran / 1 h / Ambient temperature 11: Dess-Martin periodinane / 0.67 h / Ambient temperature 12: tetrahydrofuran / 1 h / -80 - -47 °C 13: Dess-Martin periodinane / CH2Cl2 / 0.42 h / Ambient temperature 14: pyridine, CSA / CH2Cl2 / 1 h / Ambient temperature 15: 88 percent / K2CO3 / methanol / 60 h / Ambient temperature 16: 90 percent / 2,6-lutidine / CH2Cl2 17: 1.) dicyclohexylmagnesium bromide / 1.) THF, -65 to -50 deg C, 35 min, 2.) THF, -65 to -50 deg C, 40 min 18: 93 percent / TBAF / tetrahydrofuran / 34 h / Ambient temperature 19: 3 Angstroem molecular sieves, TFA / CH2Cl2 / 0.6 h / Ambient temperature View Scheme