1: 1.) (COCl)2, DMSO, 2.) Et3N / 1.) CH2Cl2, -78 deg C, 15 min, 2.) CH2Cl2, from -78 deg C to 0 deg C 2: 1.) TiCl4 / 1.) Et2O, from -78 deg C to -35 deg C, 2.) Et2O, 0 deg C, 4 h 3: 81 percent / azidotrimethylsilane, BF3*OEt2 / CH2Cl2 / 120 h / Ambient temperature 4: H2 / 10 percent Pd/C / dimethylformamide / 24 h 5: HOBT, EDAC*HCl / dimethylformamide / 3.5 h / Ambient temperature 6: hydrazine hydrate / methanol; CH2Cl2 / 48 h / Ambient temperature 7: CH2Cl2 / 1.5 h / Ambient temperature 8: lithium bis(trimethylsilyl)amide / tetrahydrofuran / 30 h / Ambient temperature 9: TFA / CH2Cl2 / 1 h / Ambient temperature 10: 92 percent / EDAC / CH2Cl2 / 2 h / 0 °C 11: 95 percent / 1.0 N NaOH / methanol / 5.5 h View Scheme