1: 100 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 12 h / Ambient temperature 2: 86 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 1) -78 deg C, 1 h, 2) to 0 deg C, 12 h 3: 71 percent / triethylamine, 1,8-diazabicyclo<5.4.0>undec-7-ene (DBU) / CH2Cl2 / 6 h / 0 °C 4: 75 percent / diisobutylaluminium hydride (DIBAL-H) / tetrahydrofuran / 1 h / 0 °C 5: 95 percent / pyridine, N,N-dimethylaminopyridine (DMAP) / CH2Cl2 / 12 h / Ambient temperature 6: 80 percent / pyridinium chlorochromate, 3 Angstroem molecular sieves / CH2Cl2 / 12 h / Ambient temperature 7: 100 percent / 50percent aq. CF3COOH / 4 h / Ambient temperature View Scheme

Multi-step reaction with 6 steps 1: 2) Dowex 50WX8 (H+) / 1) DMF, benzene, reflux, 3 h, 2) reflux, 24 h2: 96 percent / methanol / 1 h / 0 °C3: 1) oxalyl chloride, DMSO, 2) triethylamine / 1) CH2Cl2, 40 min, -60 deg C, 2) 10 min, -60 deg C4: POCl3, pyridine / Ambient temperature5: 82 percent / NaBH4 / methanol / 1.5 h / 0 °C6: 82 percent / OsO4, trimethylamine-N-oxide, pyridine, water / 2-methyl-propan-2-ol / 12 h / Heating  

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