To a mixed solution of toluene 4.0 mL, ethanol 1.2 mL and water 0.6 mL of tert-butyl 4-bromo-2-(4-fluoroanilino)benzoate 0.20 g were added 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)isoquinoline 0.17 g, sodium hydrogen carbonate 0.12 g and tetrakis(triphenylphosphine)palladium(0) 35 mg, and it was heated and refluxed under nitrogen atmosphere for 4 hours. After the reaction mixture was cooled to room temperature, tetrakis(triphenylphosphine)palladium(0) 35 mg was added to it, and it was heated and refluxed under nitrogen atmosphere for 4 hours. After the reaction mixture was cooled to room temperature, and water was added to it. The organic layer was separated and collected,dried over anhydrous magnesium sulfate after sequential washing with saturated sodium hydrogen carbonate aqueous solution and saturated sodium chloride aqueous solution, and the solvent was removed under reduced pressure. The obtained residue was refined by silica gel column chromatography [eluent; hexane:ethyl acetate=2:1] to give tert-butyl 2-(4-fluoroanilino)-4-(isoquinolin-4-yl)benzoate 0.11 g of pale red solid.
