5-Bromo-2-(trifluoromethoxy)benzaldehyde

PreparationAt 0 °C, a 1.6 mol/L hexane solution of n-butyllithium (15 mL) was added to a THF (50 mL) solution of diisopropylamine (3.5 mL). The reaction mixture was cooled to -78 °C, and 1-bromo-4-(trifluoromethoxy)benzene (6.0 g) was added. The mixture was stirred for 2 hours. Morpholine-4-carboxaldehyde (8.6 g) was then added to the reaction mixture, and the mixture was concentrated to dryness under reduced pressure. Water was added to the residue, and the mixture was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous sodium bicarbonate solution, then with brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was purified by silica gel column chromatography (solvent gradient; 0→30% ethyl acetate/hexane) to give 5-bromo-2-trifluoromethoxybenzaldehyde (5.04 g, 75%) as a colorless oil.