1: n-BuLi / tetrahydrofuran / -78 deg C, 30 min; -40 deg C to RT 2: 6percent Na-Hg, Na2HPO4 / methanol / 3 h / 0 - 20 °C 3: PPTS / ethanol / 6 h / 50 °C View Scheme

chromium(VI) oxide; sulfuric acid T=0 - 20°C; 1 h; Yield given;

Dess-Martin periodane in dichloromethane T=20°C; 3 h;

1: 96 percent / imidazole / dimethylformamide / Ambient temperature 2: 1) TMEDA, s-BuLi / 1) Et2O, cyclohexane, -78 deg C, 6 h, 2) Et2O, cyclohexane, -78 deg C -> room temperature, overnight 3: 93 percent / n-Bu4NF / tetrahydrofuran / 0 deg C, 1 h; room temperature, 2 h 4: 86 percent / N-methylmorpholine N-oxide, 4 Angstroem molecular sieves, (n-Pr)4NRuO4 / CH2Cl2 / Ambient temperature 5: 1) n-BuLi / 1) DME, hexane, -50 deg C, 30 min, 2) DME, hexane, -60 deg C, 2 h 6: 68 percent / sodium amalgam, disodium hydrogen phosphate / methanol / 3 h / Ambient temperature 7: 95 percent / Jones reagent / acetone / 0.5 h / Ambient temperature 8: 92 percent / TFA / CH2Cl2 / 0.5 h / Ambient temperature 9: 70 percent / NaBH3CN, AcOH / acetonitrile; H2O / 1.33 h / pH 7 View Scheme