Reaktion #47606

Reaktionsgleichung

borane

(S)-2-benzyloxycarbonylamino-succinic acid 1-methyl ester

→

(S)-2-benzyloxycarbonylamino-4-hydroxy-butyric acid methyl ester

Ausbeute 68.0%

Lösungsmittel

tetrahydrofuran

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeIn a flask under argon was placed
2. 2
   workup.ADDITIONAfter the addition
3. 3
   Sonstigequenched by slow addition of a 10% aqueous citric acid solution (100 mL)
4. 4
   ExtraktionThe mixture was then extracted with diethyl ether (3×50 mL)
5. 5
   Waschenwashed with a 1:1 solution of water
6. 6
   Trocknensaturated aqueous sodium chloride solution (50 mL), dried over sodium sulfate
7. 7
   Einengenconcentrated in vacuo
8. 8
   SonstigePurification by flash column chromatography (silica gel 60, 230-400 mesh; 40% ethyl acetate/hexanes to 80% ethyl acetate/hexanes)

Vorschrift

In a flask under argon was placed (S)-2-benzyloxycarbonylamino-succinic acid 1-methyl ester (7.00 g, 24.89 mmol) in tetrahydrofuran (15 mL) and cooled to −5° C. To this mixture was added a 1.0M solution of borane in tetrahydrofuran (50.6 mL, 50.6 mmol), slowly over a 15 min period. After the addition was complete, the mixture was stirred at 0° C. for 5 h and then quenched by slow addition of a 10% aqueous citric acid solution (100 mL) and then diethyl ether (100 mL). The mixture was then extracted with diethyl ether (3×50 mL) and the organic layers were combined and washed with a 1:1 solution of water:saturated aqueous sodium chloride solution (50 mL), dried over sodium sulfate and concentrated in vacuo. Purification by flash column chromatography (silica gel 60, 230-400 mesh; 40% ethyl acetate/hexanes to 80% ethyl acetate/hexanes) afforded (S)-2-benzyloxycarbonylamino-4-hydroxy-butyric acid methyl ester (4.50 g, 68%) as a colorless viscous oil.

Quelle