反应详情

To a solution of 0.250 g (1.087 mmol) of 3-methyl-4-vinylbenzofuran-2-carboxylic acid ethyl ester (Example 87, Step 1) in 7.5 mL of dioxane and 2.5 mL of water was added 0.272 mL of 2.5 weight % osmium tetroxide in t-butanol (0.022 mmol) and the reaction was stirred for 10 minutes at room temperature, turning yellow-brown in color. Sodium periodate (0.488 g, 2.282 mmol) was then added in several portions over 30 minutes and a white precipitate formed. The reaction was stirred at room temperature for 2 h and then diluted with water and extracted with ethyl acetate. The combined organics were washed with water and brine, dried over magnesium sulfate, filtered and concentrated in vacuo. The residue was chromatographed on silica gel eluting with ethyl acetate/hexanes (1:10) to provide 0.225 g of 4-carbonyl-3-methylbenzofuran-2-carboxylic acid ethyl ester.

1. customa white precipitate formed
2. stirringThe reaction was stirred at room temperature for 2 h
3. extractionextracted with ethyl acetate
4. washThe combined organics were washed with water and brine
5. dry with materialdried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was chromatographed on silica gel eluting with ethyl acetate/hexanes (1:10)