1: diisopropylethylamine / CH2Cl2 / 3 h / Ambient temperature 2: 95 percent / Fe(O), Et3N, HMPA / diethyl ether; tetrahydrofuran / 1.) r.t., 10 min, 2.) r.t., 2 h 3: 1.) O3, 2.) Me2S / 1.) CH2Cl2, -78 deg C 5: tetrahydrofuran; hexane 6: 97 percent / CF3COOH / CH2Cl2 / 1 h / Ambient temperature 7: PDC, 4 Angstroem molecular sieves / dimethylformamide / 20 h / Ambient temperature 9: 3 N LiOH / methanol / 1 h / Heating 10: Li, liq. NH3 / tetrahydrofuran / 0.5 h / -78 °C View Scheme