13803-39-9

52938-97-3

GENERAL METHODS: To a mixed solution of 5-(3-chlorophenyl)-2-furaldehyde (19a) (206 mg, 1.00 mmol) dissolved in tert-butanol (37.5 mL) and water (7.5 mL) was added sequentially NaH2PO4 (213 mg, 1.50 mmol), 2-methyl-2-butene (0.78 mL, 7.50 mmol) and NaClO2 (228 mg, 2.50 mmol). The reaction mixture was stirred at room temperature for 11 hours. After completion of the reaction, the volatile solvent was removed by distillation under reduced pressure and water and 1N hydrochloric acid were added. The mixture was extracted with ethyl acetate (EtOAc). The organic layers were combined, washed with saturated brine, dried over anhydrous magnesium sulfate (MgSO4) and concentrated under reduced pressure to give 5-phenyl-2-furoic acid (22a) (214 mg, 97% yield) as a white solid.