1: 84 percent / chromium trioxide, periodic acid / H2O; acetone / 4 h / Ambient temperature 2: 1.) triethylamine, ethyl chloroformate, 2.) NH3 gas / 1.) CH2Cl2, -15 - -5 deg C, 1 h, 2.) -15 deg C - room temperature, 0.5 h 3: 62 percent / trifluoroacetic acid / CH2Cl2 / 4 h 4: 90 percent / sodium borohydride, CeCl3 / methanol / 0.02 h 5: 82 percent / acetic acid / 1 h 6: 96 percent / hexamethyldisilazane / pyridine / 0.08 h 7: 54 percent / toluene / 2 h / 370 °C 8: 96 percent / aq. HCl / tetrahydrofuran / 0.08 h 9: 91 percent / diisobutylaluminum hydride / tetrahydrofuran; hexane / 0.5 h / Ambient temperature 10: 62 percent / trifluoroacetic acid, dimethyl sulfoxide / CH2Cl2 / 1 h / -78 °C View Scheme