Реакция #343585

Уравнение реакции

N-bromosuccinimide

ethyl 2-hydroxymethyl-2,3-dihydrobenzofuran-5-carboxylate

triphenylphosphine

→

purified product

Выход 82.5%

Ethyl 2-bromomethyl-2,3-dihydrobenzofuran-5-carboxylate

Выход 82.5%

Растворители

methylene chloride

methylene chloride

Условия реакции

Обработка

1. 1
   workup.ADDITIONTo this was added, in portions over twenty minutes
2. 2
   Экстракцияextracted with water, brine
3. 3
   Сушкаdried (MgSO4)
4. 4
   ДругоеEvaporation in vacuo
5. 5
   Другоеafforded an oil which
6. 6
   Другоеwas triturated with ethyl ether
7. 7
   Фильтрацияfiltered
8. 8
   Другоеto remove insoluble triphenylphosphine oxide
9. 9
   ДругоеEvaporation of the filtrate
10. 10
    Другоеyielded 8.4 g of crude product which
11. 11
    workup.ADDITIONwas charged to a column
12. 12
    workup.ADDITIONcontaining 200 g silica gel
13. 13
    Промывкаeluted with methylene chloride

Методика

To a solution of 5.0 g (22.5 mmole) ethyl 2-hydroxymethyl-2,3-dihydrobenzofuran-5-carboxylate in 80 ml methylene chloride under nitrogen was added in one portion 6.5 (24.7 mmole) triphenylphosphine and the resulting solution was stirred for ten minutes. To this was added, in portions over twenty minutes, 4.39 g (24.7 mmole) N-bromosuccinimide and the resulting mixture was stirred overnight at room temperature. The mixture was diluted with methylene chloride, extracted with water, brine and dried (MgSO4). Evaporation in vacuo afforded an oil which was triturated with ethyl ether and filtered to remove insoluble triphenylphosphine oxide. Evaporation of the filtrate yielded 8.4 g of crude product which was charged to a column containing 200 g silica gel and eluted with methylene chloride to provide 5.29 g of purified product, TLC Rf 0.85. Mass spectrum (m/e) 286 (M+). 1H-NMR(CDCl3) ppm(delta): 3.2 (CH2Br), 3.6 (benzyl CH2).

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