1: 86 percent / PPTS / methanol / 0 °C 2: 92 percent / imidazole / dimethylformamide; CH2Cl2 / -60 °C 3: DBU / acetonitrile / 0 °C 4: 1.) methyl 2,2,2-trichloroacetimidate, Et3N, 2.) PPTS / 1.) MeCN, -20 to -15 deg C, 2.) MeOH, H2O, 20 deg C 5: 84 percent / H2O2 / H2O; tetrahydrofuran / 0 - 20 °C 6: 92 percent / Bu4NF / tetrahydrofuran / -5 - 0 °C 7: 88 percent / DIAD, PPh3 / tetrahydrofuran / 0 °C 8: 90 percent / tetrahydrofuran / 20 °C 9: Et3N / CH2Cl2 / Heating 10: TsOH / methanol / 20 °C 11: imidazole / dimethylformamide; CH2Cl2 / -60 °C 12: 91 percent / OsO4, NMO, H2O / acetone / 0 °C 13: 92 percent / TsOH / 20 °C 14: DMAP, Et3N / CH2Cl2 / 20 °C 15: Bu4NF / tetrahydrofuran / 20 °C 16: NaOH, H2O 17: 76 percent / cyclohexene / 5percent Pd/C / ethanol / Heating 18: 96 percent / HCl, H2O / methanol View Scheme