반응 #162935

반응 방정식

NaHCO3

tert-butyl ((3S,7S,8R,9S)-7-benzyl-8-(3-hydroxybutoxy)-9-methyl-2-oxo-1,5-dioxonan-3-yl)carbamate

proton sponge

trimethyloxonium tetrafluoroborate

→

tert-butyl ((3S,7S,8R,9S)-7-benzyl-8-(3-methoxybutoxy)-9-methyl-2-oxo-1,5-dioxonan-3-yl)carbamate

수율 84.7%

용매

CH2Cl2

반응 조건

후처리

1. 1
   추출extracted with CH2Cl2 (3×20 mL)
2. 2
   건조The combined organic extracts were dried over Na2SO4
3. 3
   여과filtered
4. 4
   농축concentrated
5. 5
   기타to provide a yellow oil
6. 6
   기타Purification by automated silica gel column chromatography (1-6% acetone in CH2Cl2)

실험 절차

To a solution of tert-butyl ((3S,7S,8R,9S)-7-benzyl-8-(3-hydroxybutoxy)-9-methyl-2-oxo-1,5-dioxonan-3-yl)carbamate (82 mg, 0.18 mmol, 1.00 equiv) in CH2Cl2 (1.8 mL) were added proton sponge (156 mg, 0.726 mmol, 4.00 equiv) and trimethyloxonium tetrafluoroborate (54 mg, 0.36 mmol, 2.0 equiv). The resulting suspension was stirred at room temperature for 1 h, poured into ½ sat'd NaHCO3 solution (20 mL), and extracted with CH2Cl2 (3×20 mL). The combined organic extracts were dried over Na2SO4, filtered, and concentrated to provide a yellow oil. Purification by automated silica gel column chromatography (1-6% acetone in CH2Cl2) provided tert-butyl ((3S,7S,8R,9S)-7-benzyl-8-(3-methoxybutoxy)-9-methyl-2-oxo-1,5-dioxonan-3-yl)carbamate (71 mg, 84%) as a sticky oil: 1H NMR (400 MHz, CDCl3) δ 7.32-7.23 (m, 2H), 7.23-7.13 (m, 3H), 5.18 (d, J=6.9 Hz, 1H), 5.02-4.86 (m, 1H), 4.60 (q, J=7.2 Hz, 1H), 3.94-3.75 (m, 2H), 3.75-3.62 (m, 1H), 3.62-3.41 (m, 3H), 3.36 (dd, J=10.5, 6.5 Hz, 1H), 3.33-3.22 (m, 4H), 3.21-3.04 (m, 2H), 2.29 (t, J=12.5 Hz, 1H), 2.00-1.81 (m, 1H), 1.81-1.68 (m, 2H), 1.48 (s, 3H), 1.41 (s, 9H), 1.15 (d, J=6.1 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ 172.21, 154.98, 139.93, 139.88, 129.13, 128.42, 126.10, 85.02, 80.03, 75.51, 75.45, 73.41, 73.39, 72.91, 72.58, 69.09, 68.84, 55.94, 55.89, 53.01, 47.27, 47.14, 37.41, 37.35, 35.14, 35.03, 28.27, 19.09, 18.73.

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