反应详情

温度

20 °C

Dissolve 7-bromo-5-fluorobenzofuran (2 g, 9.3 mmol) in 5 ml tetrahydrofuran under nitrogen. Add magnesium turnings (0.25 g, 1.1 equivalents) and heat to reflux to facilitate Grignard formation. In a separate flask place diethyl oxalate (1.3 mL, 2 equivalents) in 3 mL tetrahydrofuran, and cool to 0° C. under nitrogen. When Grignard formulation is complete, add via canula to the diethyl oxalate solution. Stir the reaction for 2-4 hours while slowly warming to 20° C. Extract with diethyl ether. Wash organic layer with brine. Dry over magnesium sulfate, filter and concentrate to a light yellow oil. Purifacation by column chromatography (4:1 hexanes:ethyl acetate) affords 1.74 g (79%) of an oil which solidifies upon standing. MS (ES, m/z): 237.0 (M+1).

1. temperatureto reflux
2. customthe reaction for 2-4 hours
3. extractionExtract with diethyl ether
4. dry with materialDry over magnesium sulfate
5. filtrationfilter
6. concentrationconcentrate to a light yellow oil