반응 #343585

반응 방정식

N-bromosuccinimide

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

triphenylphosphine

→

purified product

수율 82.5%

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

수율 82.5%

용매

methylene chloride

methylene chloride

반응 조건

후처리

1. 1
   workup.ADDITIONTo this was added, in portions over twenty minutes
2. 2
   추출extracted with water, brine
3. 3
   건조dried (MgSO4)
4. 4
   기타Evaporation in vacuo
5. 5
   기타afforded an oil which
6. 6
   기타was triturated with ethyl ether
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   여과filtered
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   기타to remove insoluble triphenylphosphine oxide
9. 9
   기타Evaporation of the filtrate
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    기타yielded 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
    세척eluted with methylene chloride

실험 절차

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).

출처