Ethyl chloroformate → Ethyl 5-bromo-3-oxo-2,3-dihydro-1-benzofuran-2-carboxylate

反応式

C(=O)([O-])[O-].[K+].[K+].[Br:7][C:8]1[CH:9]=[CH:10][C:11]2[O:15][CH2:14][C:13](=[O:16])[C:12]=2[CH:17]=1.Cl[C:19]([O:21][CH2:22][CH3:23])=[O:20]>CC(C)=O>[Br:7][C:8]1[CH:9]=[CH:10][C:11]2[O:15][CH:14]([C:19]([O:21][CH2:22][CH3:23])=[O:20])[C:13](=[O:16])[C:12]=2[CH:17]=1

参加物

実験手順

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.