反应详情

温度

80 °C

To a solution of (2R,3R,4S,5S,6S)-3,4,5-tris(benzyloxy)-2-((benzyloxy)methyl)-6-methoxytetrahydro-2H-pyran (28.0 g, 50.5 mmol, 1.0 equiv) in acetic acid (480 mL), was added 3M H2SO4 (120 mL, aqueous) at 0° C. The reaction was heated at 80° C. for 10 hours, cooled to room temperature, and then neutralized with saturated aqueous potassium carbonate solution. The mixture was then extracted with DCM (3×1000 mL). The combined organic layers were dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. The material thus obtained was purified by silica gel chromatography, eluting with 30% EtOAc in petroleum ether, to give (3S,4S,5R,6R)-3,4,5-tris(benzyloxy)-6-((benzyloxy)methyl)tetrahydro-2H-pyran-2-ol as a pale yellow oil (15.0 g, 54%). 1H NMR (300 MHz, DMSO-d6) δ 7.38-7.17 (m, 20H), 6.61 (d, J=4.4 Hz, 1H), 5.14-5.07 (m, 1H), 4.77 (t, J=8.5 Hz, 3H), 4.71-4.38 (m, 6H), 3.80 (dp, J=22.8, 9.1, 8.3 Hz, 3H), 3.68-3.53 (m, 2H). ESI (M+H2O) 558.2; calc for C34H36O6 540.3.

1. temperaturecooled to room temperature
2. extractionThe mixture was then extracted with DCM (3×1000 mL)
3. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customThe material thus obtained
7. customwas purified by silica gel chromatography
8. washeluting with 30% EtOAc in petroleum ether