3-(4-Fluorophenyl)-2-propenoic acid

white to light yellow crystal powder

General procedure: Under a N2 atmosphere, LiOtBu or KOtBu (3.0 mmol), H2O (2.0 mL) and acrylic acid (1.2 mmol) were added into a Schlenk reaction tube and the mixture was stirred at room temperature for 10 minutes. Then an aryl halide 2 (1.0 mmol) and Pd(II)–Im complex 1 (1.0 molpercent) were added. The mixture was stirred at 100 °C for 12 h. After cooling to room temperature, the reaction mixture was acidified by HCl (4 M) to pH 1 and extracted with EtOAc. The organic layer was washed with brine and dried over anhydrous Na2SO4. The solvent was evaporated in vacuo and the residue was purified by flash chromatography on silica gel to afford the pure product 5.General procedure: To a stirred solution of benzaldehyde (1a, 1.7 ml, 16.04mmol, 1 equiv) and malonic acid (2, 2 g, 24.06 mmol, 1.5equiv) in pyridine (5 mL) was added LiClO4 (0.34 g, 3.2mmol, 0.2 equiv) and refluxed for 5 hrs. The progress ofreaction was monitored by TLC using eluent EtOAc: nhexane(4:6). After completion of reaction, the solution wasacidified with concentrated HCl to afford a white precipitate.The precipitate was filtered and washed with water (10 ml)twice, further dried to afford 2.2 g (93percent) of 3a as the finalproduct. All synthesized compounds were characterized byIR, NMR and mass with satisfactory spectral data.General procedure: A solution of suitably substituted carbaldehyde (200mmol), propenedioic acid (20.8g, 200mmol) in pyridine (10mL, 120mmol) and piperidine (1mL) was warmed at reflux for 2h. The resultant solution was poured into 2M HCl aq. and cooled to room temperature. The solid was filtered, washed with water and recrystallized in ethanol/waterGeneral procedure: Under a N2 atmosphere, LiOtBu or KOtBu (3.0 mmol), H2O (2.0 mL) and acrylic acid (1.2 mmol) were added into a Schlenk reaction tube and the mixture was stirred at room temperature for 10 minutes. Then an aryl halide 2 (1.0 mmol) and Pd(II)–Im complex 1 (1.0 molpercent) were added. The mixture was stirred at 100 °C for 12 h. After cooling to room temperature, the reaction mixture was acidified by HCl (4 M) to pH 1 and extracted with EtOAc. The organic layer was washed with brine and dried over anhydrous Na2SO4. The solvent was evaporated in vacuo and the residue was purified by flash chromatography on silica gel to afford the pure product 5.General procedure: To a 5 mL round bottom flask equipped with a stirbar, trans-2’-hydroxychalcone 1a (1 mmol), K2CO3(1.38 g, 10 mmol), 35percent H2O2 solution (0.5 mL) and2 mL acetonitrile were added. The reaction was stirredat room temperature and monitored by TLC (thin layerchromatograph) until disappearance of the starting material.The solvent was evaporated with reduced pressure. To theresidue, it was added 1 mol L-1 hydrochloric acid, the solidwas filtered to afford 2a as white solid (133 mg, 90percent);1H NMR (300 MHz, DMSO-d6) d 7.58 (d, 1H, J 16 Hz), 7.42-7.69 (m, 5H), 6.53 (d, 1H, J 16 Hz); 13C NMR(300 MHz, DMSO-d6) d 167.7, 144.0, 134.3, 130.3, 128.9, 128.2, 119.3.Step 1

For organic synthesis