1: 1) n-butyllithium, 2) BF3*Et2O / 1) THF, hexane, -78 deg C, 5 min,2) THF, hexane, 10 min, 3) THF, hexane, -30 deg C, 2 h 2: pyridine / 15 h / Ambient temperature 3: 6percent sodium amalgam / tetrahydrofuran; methanol / 3 h / Ambient temperature 4: 77 percent / 0.3N hydrochloric acid / acetonitrile / 2 h 5: 1) t-BuOK / 1) THF, 2) THF, 30 min 6: tetrabutylammonium fluoride / tetrahydrofuran / 48 h View Scheme