1: 100 percent / 1percent HCl / tetrahydrofuran; H2O / 0.5 h / Ambient temperature 2: 72 percent / H2 / PtO2 / ethyl acetate; acetic acid / 1 h 3: 90 percent / HClO4 / 0.08 h / Ambient temperature 4: 93 percent / 5percent KOH, air / methanol; H2O / 1 h / Ambient temperature View Scheme