反応 #505935

反応方程式

hexane ethyl acetate

diisopropylamine

ethyl 2-bromo-n-butyrate

ammonium chloride

→

title compound

収率 63.0%

2,3-Diethyl maleic acid diethyl ester

収率 63.0%

溶媒

tetrahydrofuran

tetrahydrofuran

反応条件

後処理

1. 1
   workup.STIRRINGthe mixture was stirred at 0° C. for 10 min and at −90° C. for 5 min
2. 2
   workup.STIRRINGthe mixture was stirred for 30 min
3. 3
   workup.STIRRINGwith stirring
4. 4
   ろ過The reaction mixture was directly filtered
5. 5
   濃縮the filtrate was concentrated under reduced pressure
6. 6
   workup.ADDITIONThe residue was diluted with water
7. 7
   抽出extracted twice with ethyl acetate
8. 8
   洗浄the combined organic layer was washed sequentially with water and brine
9. 9
   濃縮concentrated
10. 10
    その他The residue thus obtained

実験手順

To a solution of diisopropylamine (654 mg, 6.46 mmol) in anhydrous tetrahydrofuran (5 mL) under the atmosphere of argon was added a 1.58 M n-butyl lithium-hexane solution (3.9 mL, 6.4 mmol) with stirring under ice cooling, and the mixture was stirred at 0° C. for 10 min and at −90° C. for 5 min. To the mixture, a solution of ethyl 2-bromo-n-butyrate (1.00 g, 5.13 mmol) in anhydrous tetrahydrofuran (9.5 mL) was added dropwise at −90° C., and the mixture was stirred for 30 min. Copper (I) iodide (489 mg, 2.56 mmol) was added at the same temperature, and the mixture was vigorously stirred further 5 min. The temperature was raised to 0° C. with stirring, and a saturated aqueous ammonium chloride solution (30 mL) was added. The reaction mixture was directly filtered, and the filtrate was concentrated under reduced pressure. The residue was diluted with water and extracted twice with ethyl acetate, and the combined organic layer was washed sequentially with water and brine and concentrated. The residue thus obtained was subjected to silica gel column chromatography (hexane-ethyl acetate 9:1) to give 368.4 mg of the title compound as oil (yield: 63%).

出典