反応 #162935

反応方程式

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

収率 84.7%

溶媒

CH2Cl2

反応条件

後処理

1. 1
   抽出extracted with CH2Cl2 (3×20 mL)
2. 2
   乾燥The combined organic extracts were dried over Na2SO4
3. 3
   ろ過filtered
4. 4
   濃縮concentrated
5. 5
   その他to provide a yellow oil
6. 6
   その他Purification by automated silica gel column chromatography (1-6% acetone in CH2Cl2)

実験手順

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.

出典