1: CSA / CH2Cl2 / -23 °C 2: 66 percent / Et2Zn / toluene / 0 °C 3: 77 percent / Dess-Martin reagent / CH2Cl2 4: 84 percent / H2 / Pd(OH)2 / ethanol 5: pyridine / CH2Cl2 / -45 °C 6: TBAF, AcOH / tetrahydrofuran 7: 86 percent / PPTS / benzene / Heating 8: 100 percent / K2CO3 / methanol; tetrahydrofuran 9: 100 percent / SmI2, HMPA / tetrahydrofuran; methanol 10: TBAF, BHT / tetrahydrofuran 11: NaOMe, BHT / methanol 12: 1.) PhB(OH)2, 2.) 2,6-lutidine, 3.) H2O2, NaHCO3 13: 92 percent / Dess-Martin reagent / CH2Cl2 14: 89 percent / PPTS / CH2Cl2 15: 89 percent / KHMDS / -78 °C 16: 91 percent / Pd(PPh3)4 / diethyl ether 17: 1.) NCS, 2.) 2-methoxypropene, PPTS / 1.) MeOH, 2.) CH2Cl2 18: 1.) LDA, 2.) MoO5*pyr*HMPA / 1.) THF, -23 deg C, 2.) THF, -23 deg C 19: 92 percent / DMAP / CH2Cl2 20: 68 percent / DBN / toluene / Heating 21: 86 percent / OsO4, pyridine / diethyl ether 22: 86 percent / DBU / toluene / Heating 23: PPTS, MeOH 24: imidazole / dimethylformamide 25: 97 percent / H2 / Pd(OH)2 / ethanol 26: 94 percent / pyridine / CH2Cl2 / -78 - 0 °C 27: 66 percent / DMAP / CH2Cl2 28: 83 percent / tetrahydrofuran / -78 °C 29: 88 percent / HF*pyridine / tetrahydrofuran 30: 94 percent / pyridine / CH2Cl2 31: 80 percent / TASF / tetrahydrofuran 32: 77 percent / LHMDS / tetrahydrofuran / -78 - 0 °C 33: 84 percent / Zn, aq. AcOH View Scheme

1: CSA / CH2Cl2 / -23 °C 2: 66 percent / Et2Zn / toluene / 0 °C 3: 77 percent / Dess-Martin reagent / CH2Cl2 4: 84 percent / H2 / Pd(OH)2 / ethanol 5: pyridine / CH2Cl2 / -45 °C 6: TBAF, AcOH / tetrahydrofuran 7: 86 percent / PPTS / benzene / Heating 8: 100 percent / K2CO3 / methanol; tetrahydrofuran 9: 100 percent / SmI2, HMPA / tetrahydrofuran; methanol 10: TBAF, BHT / tetrahydrofuran 11: NaOMe, BHT / methanol 12: 1.) PhB(OH)2, 2.) 2,6-lutidine, 3.) H2O2, NaHCO3 13: 92 percent / Dess-Martin reagent / CH2Cl2 14: 89 percent / PPTS / CH2Cl2 15: 89 percent / KHMDS / -78 °C 16: 91 percent / Pd(PPh3)4 / diethyl ether 17: 1.) NCS, 2.) 2-methoxypropene, PPTS / 1.) MeOH, 2.) CH2Cl2 18: 1.) LDA, 2.) MoO5*pyr*HMPA / 1.) THF, -23 deg C, 2.) THF, -23 deg C 19: 92 percent / DMAP / CH2Cl2 20: 68 percent / DBN / toluene / Heating 21: 86 percent / OsO4, pyridine / diethyl ether 22: 86 percent / DBU / toluene / Heating 23: PPTS, MeOH 24: imidazole / dimethylformamide 25: 97 percent / H2 / Pd(OH)2 / ethanol 26: 94 percent / pyridine / CH2Cl2 / -78 - 0 °C 27: 66 percent / DMAP / CH2Cl2 28: 83 percent / tetrahydrofuran / -78 °C 29: 88 percent / HF*pyridine / tetrahydrofuran 30: 94 percent / pyridine / CH2Cl2 31: 80 percent / TASF / tetrahydrofuran View Scheme