1: O.5 N HCl / tetrahydrofuran / 0.17 h / 0 °C 2: diethyl ether 3: 98 percent / SO3*pyridine complex / dimethylsulfoxide; triethylamine / 0.25 h / Ambient temperature 4: 1.) NaH / 1.) THF, RT, 30 min, 2.) THF, RT, 1 h 5: 65percent AcOH / tetrahydrofuran / 0.75 h / 50 °C 6: 83 percent / diisobutylaluminum hydride, 2,6-di-t-butyl-4-methylphenol / 1.) toluene, 5 deg C, 1 h, 2.) toluene, -78 deg C (adding), up to -10 deg C within 2.5 h, then -10 deg C, 10 min 7: 96 percent / 5percent aq KOH / ethanol / 0.33 h / 50 °C View Scheme