反应详情

2-(6-Bromo-3,4-dihydro-1H-2-benzopyran-1-yl)ethanol (1.3 g, 5.1 mmol), zinc cyanide (0.36 g, 3 mmol) and tetrakis(triphenylphosphine)palladium (0) (0.23 g, 0.20 mmol) were stirred in degassed DMF (20 mL) under nitrogen at reflux for 9 h. The reaction mixture was diluted with toluene and washed with 2M aqueous ammonia, the aqueous layer further extracted with ethyl acetate, then the combined organic extracts washed with brine. The organic extracts were dried (MgSO4), filtered and evaporated in vacuo. Purification by flash chromatography on silica, eluting with ethyl acetate/hexane (30:70 to 0:100), yielded the title compound as a light brown oil.

1. temperatureat reflux for 9 h
2. washwashed with 2M aqueous ammonia
3. extractionthe aqueous layer further extracted with ethyl acetate
4. washthe combined organic extracts washed with brine
5. dry with materialThe organic extracts were dried (MgSO4)
6. filtrationfiltered
7. customevaporated in vacuo
8. customPurification by flash chromatography on silica
9. washeluting with ethyl acetate/hexane (30:70 to 0:100)