1.1: LHMDS / tetrahydrofuran; hexane / 0.75 h / -78 °C 1.2: 72 percent / Br2 / tetrahydrofuran; hexane / 0.83 h / -78 °C 2.1: 94 percent / tetramethylguanidinium azide / CH2Cl2 / 2.25 h / 0 - 20 °C 3.1: 96 percent / LiOH; aq. H2O2 / tetrahydrofuran / 1.5 h / 20 °C 4.1: 86 percent / H2 / Pd/C / methanol / 0.5 h View Scheme