反应详情

Potassium carbonate (1.66 g, 12 mmol) is added to a solution of 5-bromo-1-benzofuran-3(2H)-one (2.13 g, 10 mmol) in acetone (25 mL). The stirred mixture is treated dropwise with ethyl chloroformate (1.05 mL, 11 mmol). The mixture is then heated at reflux for 18 h. The solids are filtered off and the filtrate concentrated in vacuo. The residue is partitioned between EtOAc and saturated aqueous NaHCO3. The layers are separated and the organic layer washed with brine, dried (Na2SO4), filtered and concentrated in vacuo. The residue is purified by silica gel chromatography (gradient elution with hexanes-EtOAc) to afford the title compound.

1. temperatureThe mixture is then heated
2. temperatureat reflux for 18 h
3. filtrationThe solids are filtered off
4. concentrationthe filtrate concentrated in vacuo
5. customThe residue is partitioned between EtOAc and saturated aqueous NaHCO3
6. customThe layers are separated
7. washthe organic layer washed with brine
8. dry with materialdried (Na2SO4)
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customThe residue is purified by silica gel chromatography (gradient elution with hexanes-EtOAc)