1: 90 percent / Dess-Martin's periodinane / CH2Cl2 / 0.5 h / Ambient temperature 2: 51 percent / nBuLi / diethyl ether; hexane / 1.) 0 deg C, 10 min; 2.) -42 deg C, 135 min 3: 6percent Na(Hg) / methanol; tetrahydrofuran / 3.5 h / -35 °C 4: LiOH / tetrahydrofuran; H2O / 18 h / Ambient temperature 5: Li/NH3(l) / ethanol / 0.5 h / -78 °C View Scheme