1: 1) KHMDS, 2) trisyl azide / 1) THF, -78 deg C, 2) THF, -78 deg C, 2 min 2: LiOH*H2O, 30percent aq. H2O2 / tetrahydrofuran; H2O / 1 h / 0 °C 3: HCl, H2 / 10percent Pd/C / tetrahydrofuran / 20 h / 2585.7 Torr 4: iPr2NEt / methanol View Scheme