[Synthesis]
GENERAL METHODS: Pyridine-3-boronic acid (1.0 mmol), homotrimethylphenyl (phenyl) iodonium trifluoromethanesulfonate (1.2 mmol), eosin Y (34.5 mg, 0.02 mmol) and sodium tert-butoxide (1.1 mmol, 25 mg) were dissolved in N,N-dimethylformamide (2.0 mL) in a borosilicate flask. The reaction was stirred for 1-2 hours at room temperature under continuous irradiation with 18 Watt LED visible light. Upon completion of the reaction (monitored by thin layer chromatography), the reaction mixture was poured into water (50 mL) and stirring was continued for 2 hours. The aqueous phase was extracted with dichloromethane (2 x 20 mL), the organic phases were combined and dried over anhydrous sodium sulfate. After concentration under reduced pressure, the residue was purified by silica gel column chromatography [eluent: ethyl acetate/petroleum ether (60-90 °C) = 1:10 to 1:4] to afford the target product, 3-phenoxypyridine (3h), as a yellowish oil.1H NMR (CDCl3, 400 MHz) δ 8.21-8.20 (m, 1H), 7.70-7.66 (m, 1H), and 7.42-7.38 (m, 2H), 7.16-7.14 (m, 2H), 7.01-6.97 (m, 1H), 6.91-6.89 (m, 1H); 13C NMR (CDCl3, 125 MHz) δ 163.8, 154.2, 147.8, 139.4, 129.7, 124.6, 121.2. 118.4, 111.5. |