1-Arylbenziodoxolones (0.1 mmol), CH2Cl2 (1 mL), and CF3COOH (100 L) were placed in a Schlenk flask. The reaction mixture was stirred for 1 min at room temperature, and then the solvent was evaporated, and the residue was dried under vacuum. CsF (0.3 mmol, 0.1 mmol), TEMPO (0.1 mmol), and dry DMF (500 L) were added to the residue under an argon atmosphere. The reaction mixture was stirred for 20-30 min at 130-150 C. Then water (3 mL or 5% NaHCO3) and CH2Cl2 (3 mL) were added to the reaction mixture. The organic layer was discarded, and HCl (100 L, 37%) and CH2Cl2 (3mL) were added to the water layer. The mixture was shaken for a minute, and then the organic layer was separated, dried with Na2SO4, and the solvent was evaporated. Finally, product 2-Fluoro-3-methylbenzoic acid was obtained after purification.
