1: 73 percent / 0.1 M aq. HCl / methanol / 6 h / 20 °C 2: 1.) sodium metaperiodate, 2.) NaBH4 / 1.) H2O, 20 deg C, 1 h, 2.) H2O, 20 deg C, 4 h 3: potassium tert-butoxide / dimethylsulfoxide / 50 °C 4: pyridine 5: HgCl2, HgO / acetone View Scheme