A mixture of 2-benzoylpyrrole (855 mg, 5 mmol), diethyl chloromalonate (973 mg, 5 mmol) and manganese(III) acetate dihydrate (4560 mg, 15 mmol) in acetic acid (30 mL) was stirred at 80° C. for four hours. The reaction was cooled to room temperature, diluted with diethyl ether and filtered. The filtrate was washed with 10% aqueous sodium hydroxide and saturated aqueous sodium chloride, dried (Na2SO4), and concentrated under reduced pressure. The residue was purified by column chromatography on silica (70-30, hexanes-ethyl acetate) to provide 1.46 g (75%) of diethyl (5-benzoylpyrrol-2-yl)acetoxymethane-dicarboxylate.
