1: 93 percent / DMAP / CH2Cl2 / -50 deg C, 15 min; RT, 45 min 2: 90 percent / LiN3 / dimethylformamide / 2 h / Ambient temperature 3: 82 percent / Bu3SnH, AIBN / toluene / 1.5 h / Heating; via Staudinger reduction, too View Scheme

1.1: DMAP / CH2Cl2 / 3 h / 0 °C 2.1: DBU / acetonitrile 3.1: pyridine 3.2: morpholine 4.1: 95 percent / Et3N*HF / tetrahydrofuran 5.1: 40 percent aq. CH3NH2 View Scheme

1: 93 percent / pyridine / 16 h / Ambient temperature 2: 81 percent / pyridine / CH2Cl2 / 5 h / -15 - 10 °C 3: 1) Et3N, 2) Et4NF; 3) NH3 / 1) DMSO, 32 h; 2) MeCN, room temp., 15 min; 3) MeOH, room temp., 22 h 4: 75 percent / PPh3 / acetic acid / 2 h / 50 °C 5: 78 percent / pyrrole / acetic acid / 1 h / 70 °C View Scheme

1: 77 percent / triethylamine, DMAP / CH2Cl2 / 0.5 h / Ambient temperature 2: 90 percent / LiCl / hexamethylphosphoric acid triamide / 1 h / Ambient temperature 3: 84 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.17 h / Ambient temperature View Scheme