1: 100 percent / p-TsOH 2: 92 percent / PhSK / dimethylformamide / 3 h / 86 °C 3: acid 4: 92 percent / EtN(i-Pr)2, (Bu)4NI / CH2Cl2 / 32 h / Heating 5: 1.) LDA, 2.) mCPBA / 1.) THF, -78 deg C, 2.) hexane, 25 deg C, 5 h 6: 95 percent / CH2Cl2 / 15 h / -45 °C 7: 63 percent / Burgess' reagent 8: 100 percent / pyridine 9: 65 percent / OsO4 10: DBU / toluene / 2 h / 105 °C 11: 75 percent / pyridine, DMAP / 24 h / 25 °C 12: 100 percent / HF*pyridine / acetonitrile / 11 h / 0 °C 13: tetrahydrofuran / 0.17 h / -78 °C 14: tetrapropylammonium perruthenate, NMO, molecular sieves / CH2Cl2 / 0.25 h / 25 °C 15: 1.) t-BuOK, 2.) benzeneseleninic anhydride, 3.) t-BuOK 16: pyridine, DMAP / 20 h / 25 °C 17: 94 percent / TASF / tetrahydrofuran / 1 h / 25 °C 18: 1.) LHMDS / 1.) THF, 2.) THF, 0 deg C, 1 h 19: HF, pyridine / acetonitrile / 1 h / 0 °C 20: H2 / Pd/C / ethanol / 1 h View Scheme