反応 #1884982

反応方程式

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

sodium borohydride

ethyl acetate hexane

→

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

収率 64.0%

溶媒

methanol

water

反応条件

後処理

1. 1
   抽出extracted with ether
2. 2
   洗浄washed with saturated aqueous NaCl
3. 3
   乾燥dried (MgSO4)
4. 4
   その他evaporated
5. 5
   その他to give a light yellow oil

実験手順

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)+.

出典