1: 96.8 percent / H2 / PtO2 / ethanol / 3 h / Ambient temperature 2: 91.7 percent / HCl (10percent) / acetone / 3 h / Ambient temperature 3: 74.2 percent / chromic acid / tetrahydrofuran / 0.17 h / 0 °C 4: 89.6 percent / NaOH (10percent) / methanol / 4 h / Ambient temperature View Scheme