反应详情

To a solution of 11-3 (4.0 g, 12.3 mmol) in methanol (150 mL) at −15° C. was added sodium borohydride (0.515 g, 13 mmol). After 10 minutes, conc. HCl was added until bubbling ceased, and then sat. NaHCO3 was added to reach pH=10. The mixture was warmed to room temperature, the methanol removed, and the residue diluted with ethyl acetate, washed with sat. NaHCO3 and brine, and dried over magnesium sulfate. Evaporation of the solvents gave a residue which was purified on a 10×50 cm Chiralpak AD column (flow=200 ml/min, A:B=20:80) (A=0.1% diethylamine/hexane, B=ethanol). Product 11-4 elutes at 21 minutes, providing 1.7 g of 11-4 (84% yield of theoretical); its enantiomer elutes at 45 minutes.

1. customuntil bubbling
2. additionsat. NaHCO3 was added
3. customthe methanol removed
4. additionthe residue diluted with ethyl acetate
5. washwashed with sat. NaHCO3 and brine
6. dry with materialdried over magnesium sulfate
7. customEvaporation of the solvents
8. customgave a residue which
9. customwas purified on a 10×50 cm Chiralpak AD column (flow=200 ml/min
10. waitProduct 11-4 elutes at 21 minutes