Water (3.0 mL), sodium carbonate (1.1 g), tert-butyl 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenylcarbamate (1.5 g), and bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)palladium(II) dichloride (30 mg) were added to an ethylene glycol dimethyl ether (10 mL) solution of methyl 4-chloro-2-nitrobenzoate (0.90 g), followed by heating to reflux under a nitrogen atmosphere for 1 hour and 30 minutes. The reaction mixture was cooled to room temperature, and then ethyl acetate and a 10% aqueous solution of citric acid were added thereto. The organic layer was separated, washed with a saturated aqueous solution of sodium chloride, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography [eluent: 95-85% hexane/ethyl acetate] to obtain 1.5 g of methyl 4-(2-(tert-butoxycarbonylamino)phenyl)-2-nitrobenzoate as a light yellow solid.
