1: 39 percent / 6 N aq. HCl / tetrahydrofuran / 72 h / Ambient temperature 2: 62 percent / BF3*Et2O / CH2Cl2 / 1 h / Ambient temperature 3: 67 percent / Raney nickel W-7 / ethanol / 3 h / Heating 4: 87 percent / LiAlH4 / tetrahydrofuran / 1 h / 0 °C 5: 77 percent / aq. potassium nitrosodisulfonate, KH2PO4 / acetone / 0.5 h / Ambient temperature View Scheme