C(=O)([O-])[O-].[K+].[K+].[OH:7][C:8]1[C:13]2[CH:14]=[CH:15][O:16][C:12]=2[CH:11]=[CH:10][CH:9]=1.[CH2:17](Br)[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1>CN(C)C=O>[CH2:17]([O:7][C:8]1[C:13]2[CH:14]=[CH:15][O:16][C:12]=2[CH:11]=[CH:10][CH:9]=1)[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1To a suspension of potassium carbonate (2.68 g, 19.4 mmol) in N,N-dimethylformamide (8 ml) was added a solution of 4-hydroxy-benzofuran (2.6 g, 19.4 mmol) in N,N-dimethylformamide (8 ml) at 2° C. under an argon atmosphere (for the preparation of 4-hydroxy-benzofuran see: G. Kneen, P. J. Maddocks, Syn. Commun. 1986, 16, 1635-1640.). After stirring for 50 min at 2° C., benzyl bromide (3.3 ml, 19.4 mmol) was added over a period of 15 min at 2° C. The suspension was stirred for additional 30 min at 2° C. and for 1.5 h at ambient temperature. After adding ice water (20 ml), the solution was extracted two times with diethyl ether. The combined extracts were washed three times with brine and dried over sodium sulfate. Evaporation of the solvent gave a yellow oil which was purified by column chromatography (silica gel, hexane) to give 4.3 g (19.2 mmol, 99%) of the title compound as colorless oil.
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