GENERAL STEPS: 4-Fluorobenzaldehyde (9.40 g, 75.8 mmol) and formylmethylenetriphenylphosphorane (30.0 g, 98.6 mmol) were suspended in toluene (150 mL), and the reaction was stirred for 12 hours at 70 °C. After completion of the reaction, the reaction mixture was treated with ethyl acetate (EtOAc) and water (H2O). The organic layer was separated, washed with saturated saline (brine), dried over anhydrous sodium sulfate (Na2SO4) and subsequently concentrated under reduced pressure. The residue was purified by column chromatography to afford unsaturated aldehyde (8.04 g, 71% yield). The resulting aldehyde (8.04 g, 53.5 mmol) was dissolved in a solvent mixture of pyridine (100 mL) and dichloromethane (50 mL) at 0 °C and iodine monochloride (17.4 g, 107 mmol) was added. After stirring at 0 °C for 5 h, the reaction was quenched with aqueous sodium thiosulfate (Na2S2O3) and treated with ethyl acetate (EtOAc). The organic layer was separated, washed with saturated saline (brine), dried over anhydrous sodium sulfate (Na2SO4) and subsequently concentrated under reduced pressure. The residue was purified by column chromatography to afford p-fluorocinnamaldehyde (10.01 g, 68% yield).1H-NMR (300 MHz, DMSO-d6) δ: 7.43 (2H, t, J = 8.5 Hz), 8.13 (2H, dd, J = 8.5, 5.5 Hz), 8.54 (1H, s), 8.84 (1H, s).
