a) 3-Formylphenylboronic acid (5.0 g, 33 mmol), guaiacol (2.8 g, 22 mmol), Cu(OAc)2 (4.0 g, 22 mmol), 4molecular sieves and pyridine (9 mL) were dissolved in anhydrous dichloromethane (150 mL). The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the mixture was filtered and concentrated. Purification by silica gel column chromatography afforded the target compound 3-(2-methoxyphenoxy)benzaldehyde as an oil (1.7 g, 23% yield).1H NMR (400 MHz, CDCl3) δ 9.95 (s, 1H), 7.58-7.54 (m, 1H), 7.47 (t, J = 7.5 Hz, 1H), 7.38-7.34 (m, 1H ), 7.26-7.19 (m, 2H), 7.08-7.02 (m, 2H), 7.01-6.95 (m, 1H), 3.82 (s, 3H).GC-MS m/z: 228.0 [M]+.
