1: 69 percent / LiHMDS / tetrahydrofuran / 1.) -72 deg C, 30 min, 2.) -72 to -20 deg C, 2 h 2: 79 percent / TFA / Ambient temperature 3: 60 percent / Et3N, diphenylphosphoryl azide / toluene 4: 67 percent / aq. LiOH, H2O2 / tetrahydrofuran / 0 °C 5: 81 percent / H2, glacial acetic acid / 10percent Pd/C View Scheme