1: 91 percent / 5percent aq. HCl / tetrahydrofuran / 24 h 3: 74 percent / 5percent aq. HCl / acetone / 96 h 4: 68 percent / Oil Violet, ozone / ethanol / -75 °C 5: 85 percent / sulphamic acid, sodium chlorite / tetrahydrofuran; H2O / 3 h 6: 87 percent / H2SO4 / acetone / 30 h 7: 52 percent / Me2S, aluminium chloride / CH2Cl2 / 24 h 8: 68 percent / 5percent aq. H2SO4 / acetone / 48 h / Heating View Scheme

Multi-step reaction with 3 steps 1: 87 percent / dioxane / 24 h / 70 °C2: 96 percent / NaIO4 / methanol; H2O / 24 h3: 95 percent / AcOH / toluene / 4 h / 100 °C