1.1: NaBH4 / methanol / 1.5 h / 20 °C 2.1: 4.13 g / H2SO4 / 0.5 h / Heating 3.1: O3 / CH2Cl2 / -78 °C 3.2: 71 percent / dimethyl sulfide / CH2Cl2 / 29.5 h / -78 - 20 °C 4.1: 100 percent / NaOH / H2O / 2 h / 20 °C 5.1: 68 percent / Fremy's salt; K2HPO4 / H2O; acetone / 1 h / 20 °C View Scheme