KIO3; iodine; sulfuric acid in water; acetonitrile T=55°C; 2 h;

1: 60 percent / NBS, AcOH / dioxane; H2O / 2 h / 25 °C 2: 65 percent / diethylaminosulfur trifluoride (DAST) / CH2Cl2 / 0.5 h / 25 °C 3: 7.5 percent / NH3 / methanol / 2 h / 25 °C View Scheme