反応 #162923

反応方程式

tert-butyl N-[(3S,7S,8R,9S)-7-benzyl-8-hydroxy-9-methyl-2-oxo-1,5-dioxonan-3-yl]-N-tert-butoxycarbonylcarbamate

proton sponge

trimethyloxonium tetrafluoroborate

→

tert-butyl N-[(3S,7S,8R,9S)-7-benzyl-8-methoxy-9-methyl-2-oxo-1,5-dioxonan-3-yl]-N-tert-butoxycarbonylcarbamate

収率 85.5%

溶媒

CH2Cl2

反応条件

後処理

1. 1
   その他removed from the cold bath
2. 2
   workup.STIRRINGstirred at room temperature for 5 h
3. 3
   workup.ADDITIONpoured into ½ sat'd NaHCO3 solution (20 mL)
4. 4
   抽出The mixture was extracted with CH2Cl2 (3×20 mL)
5. 5
   洗浄the combined organic phases were washed with 1N HCl (20 mL)
6. 6
   乾燥dried over Na2SO4
7. 7
   ろ過filtered
8. 8
   濃縮concentrated
9. 9
   その他to provide an oil
10. 10
    その他Purification by automated silica gel column chromatography

実験手順

To a solution of tert-butyl N-[(3S,7S,8R,9S)-7-benzyl-8-hydroxy-9-methyl-2-oxo-1,5-dioxonan-3-yl]-N-tert-butoxycarbonylcarbamate (250 mg, 0.521 mmol, 1.00 equiv) in CH2Cl2 (5.2 mL, 0.1 M) at 0° C. (ice water bath) were added proton sponge (335 mg, 1.56 mmol, 3.00 equiv) and trimethyloxonium tetrafluoroborate (116 mg, 0.782 mmol, 1.50 equiv). The resulting white suspension was stirred at 0° C. for 30 minutes (min), removed from the cold bath and stirred at room temperature for 5 h, and then poured into ½ sat'd NaHCO3 solution (20 mL). The mixture was extracted with CH2Cl2 (3×20 mL), and the combined organic phases were washed with 1N HCl (20 mL), dried over Na2SO4, filtered, and concentrated to provide an oil. Purification by automated silica gel column chromatography provided tert-butyl N-[(3S,7S,8R,9S)-7-benzyl-8-methoxy-9-methyl-2-oxo-1,5-dioxonan-3-yl]-N-tert-butoxycarbonylcarbamate (220 mg, 85%) as a colorless, sticky solid: IR (ATR) 2979, 2935, 2831, 1742, 1706, 1455, 1293, 1254, 1170, 1144, 1121, 1098, 1057, 913, 853, 732 cm−1; 1H NMR (400 MHz, CDCl3) δ 7.32-7.24 (m, 2H), 7.22-7.15 (dd, J=5.1, 2.6 Hz, 3H), 5.18-5.06 (dd, J=8.6, 6.3 Hz, 1H), 4.94-4.79 (dq, J=9.1, 6.3 Hz, 1H), 4.16-4.01 (dd, J=11.8, 6.3 Hz, 1H), 3.94-3.76 (dd, J=11.8, 8.7 Hz, 1H), 3.59-3.50 (d, J=10.5 Hz, 1H), 3.50-3.45 (s, 3H), 1.50-1.45 (m, 21H), 3.42-3.32 (dd, J=10.8, 6.2 Hz, 1H), 3.14-3.01 (m, 2H), 2.47-2.31 (t, J=12.4 Hz, 1H), 2.08-1.89 (s, 1H), 1.53-1.43 (s, 18H); 13C NMR (101 MHz, CDCl3) δ 169.94, 152.62, 139.87, 129.25, 128.33, 126.03, 86.42, 83.03, 75.09, 70.91, 59.58, 57.42, 46.62, 35.15, 27.92, 18.92; HRMS-ESI (m/z) [M+Na]+ calc'd for C26H39NO8Na, 516.2568. found, 516.2572.

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