1: nitrogen tetroxide / acetonitrile / 1.25 h / -20 °C 2: sodium iodide / acetonitrile / -20 - 20 °C 3: 92 percent / trifluoroacetic acid / CH2Cl2 / 23 h / 20 °C View Scheme

With  hydrogen; platinum(IV) oxide in  ethyl acetate 4.5 h;