Palladium-Catalyzed Suzuki Coupling of Aryl Bromides and Furan Boronic Acid

A Biotage microwave vial was charged with Pd(OAc)₂ (3.4 mg, 0.015 mmol), RuPhos (14 mg, 0.03 mmol) 4-bromobenzonitrile (46.0 mg, 0.25 mmol), potassium furan-2-yltrifluoroborate (46.0 mg, 0.26 mmol) and Na₂CO₃ (53.0 mg, 0.5 mmol). The test tube was sealed with a cap lined with a disposable Teflon septum, evacuated and purged (x 3). Ethanol (0.18 M, 1.4 mL) was added via syringe and the reaction was heated at 85 °C for 12 h. The reaction mixture was allowed to cool to rt and filtered through a thin pad of silica gel (elution with 25% methanol in EtOAc). The solvent was removed in vacuo and the crude product was purified by silica gel column chromatography (elution with hexane/EtOAc 7:1) to yield the pure product in 91% yield (38.49 mg, 0.23 mmol) as a white solid. ¹H NMR (500 MHz, CDCl₃) δ 7.72 (d, 1H, J = 8.5 Hz), 7.63 (d, 1H, J = 8.5 Hz), 7.52 (m, 1H), 6.80 (d, 1H, J = 3.5 Hz), 6.52 (dd, 1H, J = 1.8, 3.4 Hz). ¹³C NMR (125.8 MHz, CDCl₃) δ 152.1, 143.8, 134.8, 132.7, 124.1, 119.0, 112.3, 110.4, 108.3.