1: 1.) triphenylphosphine, diisopropyl diazodicarboxylate / 1.) toluene, 0 deg C, 30 min, 2.) 130 deg C, 0.01 mmHg, 2.5 h 2: 67 percent / aq. HClO4 / 4 h / 20 °C 3: 1.) PhCO2H, DEAD, Ph3P, 2.) K2CO3, MeOH / 1.) THF, 0 deg C, 10 min, 2.) 20 deg C, 45 min 4: NEt3 / CH2Cl2 / 0.17 h / 0 °C 5: 1.) caesium acetate, 2.) K2CO3, MeOH / 1.) DMF, 40-50 deg C, 24 h, 2.) 20 deg C, 1 h 6: 100 percent / H2, AcOH / Pd black / 18 h View Scheme

1: 1.) triphenylphosphine, diisopropyl diazodicarboxylate / 1.) toluene, 0 deg C, 30 min, 2.) 130 deg C, 0.01 mmHg, 2.5 h 2: 67 percent / aq. HClO4 / 4 h / 20 °C 3: 100 percent / H2, AcOH / Pd black / 18 h View Scheme

1.1: pyridine; 1H-imidazole; 4-(N,N-dimethlyamino)pyridine / 2 h / 0 - 20 °C / Inert atmosphere 2.1: triethylamine / dichloromethane / 0.25 h / 0 °C / Inert atmosphere 3.1: hydrogenchloride / methanol; water / 2 h / 0 - 20 °C 3.2: 3 h / 0 - 20 °C 4.1: hydrogen bromide / acetic acid; acetone / 0.5 h / 0 °C / Inert atmosphere 5.1: palladium 10 on activated carbon; formic acid; hydrogen / methanol / 2 h / 20 °C 6.1: sodium azide / water; N,N-dimethyl-formamide / 12 h / 90 - 100 °C View Scheme