[CH3:1][O:2][C:3]1[CH:19]=[CH:18][C:6]2[C:7](OS(C(F)(F)F)(=O)=O)=[CH:8][O:9][C:5]=2[CH:4]=1.[C]=[O:21].[CH2:22]([OH:24])C.C(N([CH2:30][CH3:31])CC)C>CN(C)C=O.CC([O-])=O.CC([O-])=O.[Pd+2]>[CH2:30]([O:21][C:22]([C:7]1[C:6]2[CH:18]=[CH:19][C:3]([O:2][CH3:1])=[CH:4][C:5]=2[O:9][CH:8]=1)=[O:24])[CH3:31]In a steel high-pressure reaction vessel, a solution of trifluoro-methanesulfonic acid 6-methoxy-benzofuran-3-yl ester (9.10 g, 30.7 mmol) in dimethylformamide (120 mL) is bubbled with carbon monoxide gas for 10 minutes. Ethanol (60 mL), triethylamine (9.25 mL), Pd(OAc)2 (0.20 g), bis-(1,3-diphenylphosphino)propane (0.38 g) are added to the reaction mixture. The mixture vessel is sealed, charged with carbon monoxide (10 g, 30 psi), and heated to 80° C. for 4.5 hours. The mixture is concentrated under reduced pressure and diluted with water (300 mL), and extracted with EtOAc (150 mL×2). The combined organic layers are dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude product is purified via flash chromatography eluting with 15% EtOAc/Hexanes. The appropriate fractions are combined and concentrated under reduced pressure to afford the title compound (5.50 g, 81%). 1H NMR (400 MHz, CDCl3): δ 8.16 (s, 1H), 7.88 (d, 1H), 7.01 (s, 1H), 6.96 (d, 1H), 4.38 (q, 2H), 3.81 (s, 3H), 1.40 (t, 3H).
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