반응 #89572

반응 방정식

proton sponge

(S)-2-tert-butoxycarbonylamino-3-hydroxy-propionic acid benzyl ester

trimethyloxonium tetrafluoroborate

→

(S)-2-tert-butoxycarbonylamino-3-methoxy-propionic acid benzyl ester

수율 69.6%

용매

dichloromethane

반응 조건

후처리

1. 1
   농축the solution was concentrated
2. 2
   workup.DISSOLUTIONthe residue was dissolved in ethyl acetate
3. 3
   여과the solution filtered through a pad of celite
4. 4
   세척The filtrate was washed with 1 M HCl and brine
5. 5
   건조The organic layers were dried over MgSO4
6. 6
   여과filtered
7. 7
   농축concentrated in vacuo

실험 절차

To a solution of the compound of Formula XII(a), (S)-2-tert-butoxycarbonylamino-3-hydroxy-propionic acid benzyl ester (1.7 g, 5.76 mmol) in dichloromethane (50 mL) was added trimethyloxonium tetrafluoroborate (1.11 g, 7.50 mmol), followed by the portion-wise addition of proton sponge (1.61 g, 7.50 mmol). After stirring for 24 hrs at RT, the solution was concentrated, and the residue was dissolved in ethyl acetate, and the solution filtered through a pad of celite. The filtrate was washed with 1 M HCl and brine. The organic layers were dried over MgSO4, filtered, and concentrated in vacuo. Silica-gel flash chromatography with 5% to 15% ethyl acetate in hexanes afforded the compound of Formula XIII(b), (S)-2-tert-butoxycarbonylamino-3-methoxy-propionic acid benzyl ester (1.24 g, 69.6%) as a colorless oil. 1H NMR (300 MHz, CDCl3): δ (ppm) 7.35-7.29 (m, 5H), 4.90-4.87 (m, 1H), 4.51 (s, 2H), 3.92-3.87 (m, 1H), 3.80-3.78 (m, 1H), 3.56 (dd, 2H), 3.42 (dd, 1H), 3.33 (s, 3H), 1.42 (s, 9H).

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