1: 1.) O3, 2.) Me2S, 3.) NaBH4 2: aq. NaIO4 / CH2Cl2 / 0 °C 3: 67 percent / NaBH(OAc)3 / benzene 4: 1.) BuLi, HMPA / 1.) THF, 0 deg C, 2.) THF, RT, 9 h 5: 1.) (COCl)2, DMSO, 2.) Et3N 6: 100 percent / BuLi / tetrahydrofuran / -78 - 0 °C 7: 75 percent / toluene / 36 h / 200 °C 8: 80 percent / 1 N aq. HCl / tetrahydrofuran; acetone 9: 72 percent / NaBH4, CeCl3 / ethanol 10: 74 percent / diethyl azodicarboxylate, Ph3P, BzONa / tetrahydrofuran 11: 81 percent / (MeO)3BF4 12: 79 percent / ethanol. NaOEt 13: 99 percent / imidazole / dimethylformamide 14: 75 percent / tetrahydrofuran / Ambient temperature 15: 89 percent / tetrabutylammonium fluoride / diethyl ether / Ambient temperature 16: 1.) Bu3SnH, AIBN, 2.) SiO2 / 1.) benzene 17: 90 percent / m-CPBA, NaHCO3 18: 70 percent / BF3*Et2O / -78 - 20 °C 19: NH2OH*HCl, NaOAc / ethanol 20: carbonyldiimidazole / CH2Cl2 / Ambient temperature 21: 1.) LiNEt2, 2.) 2,6-di-tert-butyl-4-methylphenol / 1.) THF, 0 deg C, 30 min, 2.) THF, 30 min 22: 2.) H2O / 1.) THF, -78 deg C 23: 96 percent / H2 / 10percent Pd/C / ethanol 24: 74 percent / Et3N / benzene 25: 97 percent / TsOH / methanol / 24 h / Ambient temperature View Scheme