1: 65percent AcOH / tetrahydrofuran / 0.75 h / 50 °C 2: 83 percent / diisobutylaluminum hydride, 2,6-di-t-butyl-4-methylphenol / 1.) toluene, 5 deg C, 1 h, 2.) toluene, -78 deg C (adding), up to -10 deg C within 2.5 h, then -10 deg C, 10 min 3: 96 percent / 5percent aq KOH / ethanol / 0.33 h / 50 °C View Scheme