1: 83 percent / pyridinium p-toluenesulfonate / ethanol / 3 h / 50 °C 2: 80 percent / PCC / CH2Cl2 / 4 h View Scheme

1: 99 percent / DIBAL-H / toluene / 0.5 h / -78 °C 2: 67 percent / MnO2 / CH2Cl2 / 24 h 3: 95 percent / n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 10 min; 2.) from -78 deg C to r.t. 4: 85 percent / CSA / methanol / 16 h / Ambient temperature 5: 64 percent / pyridine*SO3, Et3N / dimethylsulfoxide / 0.17 h View Scheme

1: LiAl(OC2H5)2H2 / diethyl ether 2: pyridinium chlorochromate / CH2Cl2 View Scheme

1: 99 percent / DIBAL-H / toluene / 0.5 h / -78 °C 2: 67 percent / MnO2 / CH2Cl2 / 24 h 3: 95 percent / n-BuLi / tetrahydrofuran; hexane / 1.) -78 deg C, 10 min; 2.) from -78 deg C to r.t. 4: 85 percent / CSA / methanol / 16 h / Ambient temperature View Scheme