Triphenylphosphine → 4-(4-(Trifluoromethyl)phenyl)pyridine 1-oxide

Participants

Reaction Steps

A solution of 4-(trifluoromethyl)phenylboronic acid (1.78 g, 9.37 mmol) in DME (10 mL) and aqueous K2CO3 (12 mL, 1.8 M) was degassed with argon for 20 minutes. Triphenylphosphine (797 mg, 3.04 mmol), palladium(II)acetate (174 mg, 0.775 mmol), and 4-chloropyridine 1-oxide (1.00 g, 7.72 mmol) were added sequentially, and the mixture was heated to reflux under an argon atmosphere. After stirring at reflux for 14 h, the mixture was allowed to cool and then filtered. The filtrate was diluted with H2O (25 mL) and extracted with EtOAc (3×25 mL). The organics were dried over Na2SO4, filtered and concentrated to dryness. Purification by flash column chromatography (silica gel, CH2Cl2/MeOH, 95:5) gave the title compound (465 mg, 25%) as white crystals: 1H NMR (500 MHz, CDCl3) δ 8.29 (d, J=7.2 Hz, 2H), 7.75 (d, J=8.3 Hz, 2H), 7.69 (d, J=8.2 Hz, 2H), 7.52 (d, J=7.2 Hz, 2H); ESI MS m/z 240 [M+H]+.

Provenance & Evidence