A mixture of 2-benzoylpyrrole (855 mg, 5 mmol), diethyl malonate (800 mg, 5 mmol), manganese(III) acetate dihydrate (4560 mg, 15 mmol) and sodium acetate (820 mg, 10 mmol) in acetic acid (30 mL) was stirred at 70° C. under a nitrogen atmosphere. The reaction mixture was 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 eluting with hexane/ethyl acetate (70:30) to provide 1.00 g (57%) of diethyl (5-benzoylpyrrol-2-yl)acetoxy-methanedicarboxylate.
