Ethyl Acetate → 4-[(5E)-5-(6-fluoro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2,2-dimethyl-2,5-dihydrofuran-3-yl]benzaldehyde

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a mixture of (3E)-3-(4-bromo-5,5-dimethylfuran-2(5H)-ylidene)-6-fluoro-1,3-dihydro-2H-indol-2-one (2.0 g, 6.17 mmol), 4-formyl phenylboronic acid (1.85 g, 12.3 mmol), aqueous potassium carbonate (1M, 31 mL, 31 mmol) in THF (120 mL) under a nitrogen atmosphere, was added palladium(0)tetrakis(triphenylphosphine) (356 mg, 0.3 mmol, 5 mol %). The mixture was heated at 65° C. overnight (20 h). The reaction was cooled to room temperature and ethyl acetate (500 mL) was added. The organic phase was washed with water (100 mL×2), dried over sodium sulfate, and evaporated. The residue was purified by silica gel column chromatography (5% CH3OH/CH2Cl2 elution). Trituration of the product obtained from the column chromatography with ethyl acetate/hexane (1/1), followed by isolation of the precipitate by filtration, provided 4-[(5E)-5-(6-fluoro-2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2,2-dimethyl-2,5-dihydrofuran-3-yl]benzaldehyde as a red orange solid (1.1 g, yield 51%).

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