反应详情

To a solution of (34) in CH2Cl2, stirring under nitrogen at 0° C., was added 2,2-dimethoxypropane (29.5 mL, 237.9 mmol) and p-toluene sulfonic acid monohydrate (9.050 g, 47.58 mmol). The mixture was removed from the ice bath after 15 minutes and stirred at room temperature for 1.5 hours. The reaction mixture was poured into 50 mL of saturated NaHCO3 (aq) and extracted with diethyl ether (3×50). The organic layer was extracted with NaHCO3 and brine, then dried over anhydrous MgSO4, filtered and concentrated under reduced pressure. The crude material was purified by flash chromatography on SiO2 (1:1 EtOAc/Hexanes) to yield 7.659 g (62%, 3 steps) of a clear liquid.

1. customThe mixture was removed from the ice bath after 15 minutes
2. additionThe reaction mixture was poured into 50 mL of saturated NaHCO3 (aq)
3. extractionextracted with diethyl ether (3×50)
4. extractionThe organic layer was extracted with NaHCO3 and brine
5. dry with materialdried over anhydrous MgSO4
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe crude material was purified by flash chromatography on SiO2 (1:1 EtOAc/Hexanes)
9. customto yield 7.659 g (62%, 3 steps) of a clear liquid