4-(5-Bromo-4-methylpyrimidin-2-yl)morpholine (372 mg), (2-fluoro-3-formylphenyl)boronic acid (315 mg), and potassium phosphate (918 mg) were mixed with toluene (10 ml) and water (10 ml), and palladium acetate (16 mg) and dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (59 mg) were added thereto, followed by stirring at 100° C. for 4 hours. (2-Fluoro-3-formylphenyl)boronic acid (315 mg), potassium phosphate (918 mg), palladium acetate (16 mg), dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (59 mg), and water (1 ml) were added to the reaction mixture, followed by stirring at 100° C. overnight. The reaction mixture was cooled to room temperature, CHCl3 and water were then added thereto, and the insoluble matter was removed by filtration. The organic layer of the filtrate was washed with water and saturated brine, dried over Na2SO4, and then concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (EtOAc/hexane/CHCl3) to obtain 2-fluoro-3-[4-methyl-2-(morpholin-4-yl)pyrimidin-5-yl]benzaldehyde (282 mg).
