1: NaHCO3 / H2O; diethyl ether / 4 h / Ambient temperature 2: pyridine / 16 h / 8 - 10 °C 3: aq. TFA / 4 h / Ambient temperature 4: pyridine / Ambient temperature 5: 1.) hexamethyldisilazane, ammonium sulfate, 2.) trimethylsilyl triflate / 1.) reflux, 2.) MeCN, reflux, 5 h 6: 65 percent / Cs2CO3 / acetonitrile / 3 h / Ambient temperature 7: 66 percent / NH3 / methanol / Ambient temperature 8: 74 percent / 4-(dimethylamino)pyridine / acetonitrile / 24 h / Ambient temperature 9: 77 percent / K2CO3 / acetone / 8 h / Heating View Scheme

1: 85 percent / NaBH4 / H2O; ethanol / 4 h / Ambient temperature 2: pyridine / 1 h / Ambient temperature 3: pyridine, 80percent aq. hydrazine / 60 h / Ambient temperature 4: 82 percent / 4-(dimethylamino)pyridine, diethylaminosulfur trifluoride / CH2Cl2 / 18 h / -10 - 20 °C 5: 47 percent / CH3COOH, H2SO4 6: 1.) bis(trimethylsilyl)acetamide, 2.) trimethylsilyl triflate, 3.) 80percent aq. NH2NH2 7: 61 percent / NH3 / methanol / 48 h / Ambient temperature View Scheme

sodium tetrahydroborate in methanol T=20°C; 3 h; stereoselective reaction;

1: sodium tetrahydroborate / methanol / 3 h / 20 °C 2: sodium hydride / N,N-dimethyl-formamide / 0 °C 3: sulfuric acid / acetic acid / 24 h / 20 °C View Scheme