Реакция #975121

Уравнение реакции

n-butyllithium

diisopropylamine

cinnamyl bromide

methyl (3R)-3-hydroxybutanoate

→

methyl (2R,3R)-2-[(2E)-3-phenyl-2-propen-1-yl]-3-hydroxybutanoate

Выход 85.0%

Растворители

THF

HMPA

Условия реакции

Обработка

1. 1
   ТемператураThe reaction mixture is cooled to −78.degree
2. 2
   Температураto warm to 0.degree
3. 3
   workup.STIRRINGand stirred for 16 h
4. 4
   ДругоеThe reaction mixture is quenched by addition 30 mL of saturated aqueous ammonium chloride solution
5. 5
   workup.ADDITIONis poured into 400 mL of 1 M hydrochloric acid
6. 6
   Экстракцияis extracted with two 500 mL portions of ethyl acetate
7. 7
   СушкаThe combined organic layers are dried over magnesium sulfate
8. 8
   Концентрированиеconcentrated in vacuo
9. 9
   Другоеpurified by silica gel chromatography (elution with 25% ethyl acetate-hexanes)

Методика

To a solution of diisopropylamine (47.1 g, 466.1 mmol) in THF (500 mL) cooled to −50.degree. C. is added n-butyllithium (466.1 mmol, 2.5M in hexanes) and the resulting solution is stirred at −50.degree. C. for 0.5 h. The reaction mixture is cooled to −78.degree. C. followed by slow addition of methyl (3R)-3-hydroxybutanoate (25 g, 211.9 mmol). After 0.5 h a solution of cinnamyl bromide (45.9 g, 233.0 mmol) in HMPA (10 mL) is added and the reaction mixture is allowed to warm to 0.degree. C. and stirred for 16 h. The reaction mixture is quenched by addition 30 mL of saturated aqueous ammonium chloride solution, is poured into 400 mL of 1 M hydrochloric acid, and is extracted with two 500 mL portions of ethyl acetate. The combined organic layers are dried over magnesium sulfate, concentrated in vacuo, and purified by silica gel chromatography (elution with 25% ethyl acetate-hexanes) to afford methyl (2R,3R)-2-[(2E)-3-phenyl-2-propen-1-yl]-3-hydroxybutanoate as a yellow oil (42 g, 85% yield).

Источник