1: 80 percent / pyridinium chlorochromate, 3 Angstroem molecular sieves / CH2Cl2 / 12 h / Ambient temperature 2: 100 percent / 50percent aq. CF3COOH / 4 h / Ambient temperature View Scheme

Multi-step reaction with 5 steps 1: 100 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 12 h / Ambient temperature2: 86 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 1) -78 deg C, 1 h, 2) to 0 deg C, 12 h3: 71 percent / triethylamine, 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / CH2Cl2 / 6 h / 0 °C4: 75 percent / diisobutylaluminium hydride (DIBAL-H) / tetrahydrofuran / 1 h / 0 °C5: 95 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 12 h / Ambient temperature