反应 #1884982

反应方程式

isopropyl 1-(tert-butoxycarbonyl)pyrrolidin-5-one-2(S)-carboxylate

sodium borohydride

ethyl acetate hexane

→

isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate

收率 64.0%

溶剂

methanol

water

反应条件

后处理

1. 1
   萃取extracted with ether
2. 2
   洗涤washed with saturated aqueous NaCl
3. 3
   干燥dried (MgSO4)
4. 4
   其他evaporated
5. 5
   其他to give a light yellow oil

实验过程

To a solution of isopropyl 1-(tert-butoxycarbonyl)pyrrolidin-5-one-2(S)-carboxylate (product of step 26B, 49.5 g, 183 mmol) in methanol (300 mL) was added sodium borohydride (10.0 g, 263 mmol) in ˜1 g portions over 1.5 hours. The reaction was stirred under nitrogen for another 10 minutes. It was diluted with water, extracted with ether, combined organic fractions washed with saturated aqueous NaCl, dried (MgSO4) and evaporated to give a light yellow oil. Flash chromatography (silica gel, 20-30% ethyl acetate/hexane) gave 31.8 g (64%) of isopropyl 2(S)-(tert-butoxycarbonylamino)-5-hydroxypentanoate as a colorless syrup: 1H NMR (300 MHz, Chloroform-D) δ 5.16 (br d, 1 H, J=7.3 Hz), 5.03 (sept., 1 H, J=6.2 Hz), 4.28 (br d, 1 H, J=6.2 Hz), 3.67 (br dd, J=10.2, 5.5 Hz), 1.94-1.79 (m, 2 H), 1.76-1.67 (m, 1 H), 1.66-1.56 (m, 2 H), 1.43 (s, 9 H), 1.25 (d, 3 H, J=6.2 Hz), 1.23 (d, 3 H, J=6.2 Hz). LCMS m/z 276 (M+H)+.

来源