[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[CH:9][O:8][CH:7]=1)=[O:5])[CH3:2].BrBr.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(N(CC)CC)C.O.Cl.[C:41]([OH:44])(=[O:43])C>CN(C)C=O.C([O-])(=O)C.[Pd+2].C([O-])(=O)C>[CH2:1]([O:3][C:4]([C:6]1[CH:10]=[C:9]([C:41]([OH:44])=[O:43])[O:8][CH:7]=1)=[O:5])[CH3:2]
3-Furancarboxylic acid ethyl ester (1.4 g, 10.0 mmol) was dissolved in acetic acid (10 mL), bromine (1.6 g, 10.0 mmol) was added, and the mixture was stirred overnight. The solvent was evaporated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=80/20). The obtained crude fraction was dissolved in N,N-dimethylformamide (15 mL), palladium acetate (0.18 g, 0.78 mmol), triphenylphosphine (0.41 g, 1.55 mmol), triethylamine (2.2 mL, 15.5 mmol), and water (0.7 mL, 38.8 mmol) were added, and the mixture was stirred at 80° C. overnight under a carbon monoxide atmosphere. 1N Hydrochloric acid was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The obtained residue was purified by high performance liquid chromatography to give the title compound (0.47 g).
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