[CH:1]([C:3]1[N:4]([CH2:9][C:10]([O:12][CH2:13][CH3:14])=[O:11])[CH:5]=[C:6](I)[CH:7]=1)=[O:2].P([O-])([O-])([O-])=O.[K+].[K+].[K+].[C:23]1(B(O)O)[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=1>CN(C)C=O.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[CH:1]([C:3]1[N:4]([CH2:9][C:10]([O:12][CH2:13][CH3:14])=[O:11])[CH:5]=[C:6]([C:23]2[CH:28]=[CH:27][CH:26]=[CH:25][CH:24]=2)[CH:7]=1)=[O:2]A solution of ethyl 2-(2-formyl-4-iodo-pyrrol-1-yl)acetate (3.0 g, 9.77 mmol) in dimethylformamide (25 mL) was purged with argon gas for 10 min. Bis-(triphenylphosphine)-palladium(II) chloride (0.48 g, 0.68 mmol) was added and the mixture was purged with argon gas for 5 min. Anhydrous potassium phosphate (6.18 g, 29.3 mmol) and phenylboronic acid (1.43 g, 11.7 mmol) were added successively and the reaction mixture purged with argon gas for 10 min, then heated to 110° C. and maintained at that temperature for 4 h. The resulting mixture was allowed to cool to ambient temperature and diethyl ether added. The reaction mixture was filtered, the filtrate being washed with water and the separated aqueous phase being further extracted with diethyl ether. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to afford the crude product. Purification by column chromatography over silica gel (100-200 mesh) using 8% ethyl acetate in petroleum ether as eluent afforded ethyl 2-(2-formyl-4-phenyl-pyrrol-1-yl)acetate (680 mg, 27%).
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