1: 92 percent / Bu4NF / tetrahydrofuran / -5 - 0 °C 2: 88 percent / DIAD, PPh3 / tetrahydrofuran / 0 °C 3: 90 percent / tetrahydrofuran / 20 °C 4: Et3N / CH2Cl2 / Heating 5: TsOH / methanol / 20 °C 6: imidazole / dimethylformamide; CH2Cl2 / -60 °C 7: 91 percent / OsO4, NMO, H2O / acetone / 0 °C 8: 92 percent / TsOH / 20 °C 9: DMAP, Et3N / CH2Cl2 / 20 °C 10: Bu4NF / tetrahydrofuran / 20 °C 11: NaOH, H2O 12: 76 percent / cyclohexene / 5percent Pd/C / ethanol / Heating 13: 96 percent / HCl, H2O / methanol View Scheme