反应详情

温度

-10 °C

To a solution of (3S*,4S*)-pyrrolidine-1,3,4-tricarboxylic acid 1-tert-butyl ester 3-ethyl ester (10 g, 34.8 mmol) in THF (180 mL), a solution of borane dimethylsulfide complex (2N in THF, 24.4 mL, 48.7 mmol) is added slowly at −10° C. The mixture is stirred at −10° C. for 20 min, then allowed to reach RT and further stirred for 4 h. MeOH is carefully added (exothermic!), and the mixture is concentrated under reduced pressure. MeOH is again added, and the mixture is concentrated. This operation is repeated 3 times, then the mixture is finally taken up into a saturated aqueous solution of NaHCO3 and extracted 3 times with CH2Cl2. The combined organic extracts are dried over Na2SO4, filtered and concentrated. The crude material is purified by flash chromatography on silica gel (eluent: CH2Cl2/MeOH from 100:0 to 95:5) to give the title compound as product. TLC, Rf (AcOEt)=0.52. MS (LC-MS): 174.1 [M+H-Boc]+.

1. customto reach RT
2. stirringfurther stirred for 4 h
3. concentrationthe mixture is concentrated under reduced pressure
4. additionMeOH is again added
5. concentrationthe mixture is concentrated
6. extractionextracted 3 times with CH2Cl2
7. dry with materialThe combined organic extracts are dried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. customThe crude material is purified by flash chromatography on silica gel (eluent: CH2Cl2/MeOH from 100:0 to 95:5)