反应详情

To a mixed solution of 6-hydroxy-benzofuran-2-carboxylic acid ethyl ester (200 mg, 967 μmol) in tetrahydrofuran (4 mL) and N,N-dimethylformamide (4 mL) were added diphenylindonium iodine (395 mg, 967 μmol) and potassium t-butoxide (109 mg, 967 μmol) at 0° C., which was stirred at room temperature for 40 minutes under nitrogen atmosphere. After further stirring for 3 hours at 60° C., water was added to the reaction solution at room temperature followed by extraction with ethyl acetate, washing the organic layer with sat. NaCl, drying over anhydrous magnesium sulfate and filtering. The filtrate was concentrated under a reduced pressure and the residue was purified by silica gel column chromatography (hexane:ethyl acetate=20:1) to obtain the title compound (189 mg, 69%) as a colorless oil.

1. stirringAfter further stirring for 3 hours at 60° C.
2. extractionfollowed by extraction with ethyl acetate
3. washwashing the organic layer with sat. NaCl
4. dry with materialdrying over anhydrous magnesium sulfate
5. filtrationfiltering
6. concentrationThe filtrate was concentrated under a reduced pressure
7. customthe residue was purified by silica gel column chromatography (hexane:ethyl acetate=20:1)