反应详情

温度

-78 °C

To a solution of 1-bromo-2,3-difluorobenzene (19.5 g, 0.10 mol) in dry diethyl ether (120 mL), under nitrogen at −78° C., was added dropwise, n-hexyllithium (2.3 M in hexane, 41.7 ml, 0.096 mol). The mixture was stirred for 1 min after which a solution of 1,3-dichloroacetone (12.2 g, 0.096 mol) in dry diethyl ether (30 mL) was added dropwise. The resulting mixture was stirred at −78° C. for 1 h and then brought to ambient temperature and stirred for 1 h. Aqueous hydrochloric acid (50 mL. 10%) was added and the mixture was extracted with ethylacetate (2×50 ml). The combined organic phase was washed with brine, dried (Na2SO4), filtered and evaporated to dryness. The crude product was purified by flash column chromatography on silica gel (ethylacetate/isooctane, 1:9 to 1:1) to give the title compound (11.8 g, 48%). MS m/z (rel. intensity, 70 eV) 241 (M+, 1), 193 (33), 191 (bp), 141 (11), 127 (68).

1. additionwas added dropwise
2. custombrought to ambient temperature
3. stirringstirred for 1 h
4. extractionthe mixture was extracted with ethylacetate (2×50 ml)
5. washThe combined organic phase was washed with brine
6. dry with materialdried (Na2SO4)
7. filtrationfiltered
8. customevaporated to dryness
9. customThe crude product was purified by flash column chromatography on silica gel (ethylacetate/isooctane, 1:9 to 1:1)