Water (1.2 mL), 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.25 g), sodium bicarbonate (0.21 g), and bis(triphenylphosphine)palladium(II) dichloride (14 mg) were added to an ethylene glycol dimethyl ether (4 mL) solution of benzyl 2-(benzyloxy)-5-bromobenzoate (0.40 g), followed by heating to reflux under a nitrogen atmosphere for 2 hours. The reaction mixture was cooled to room temperature, and then 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine (0.12 g), sodium bicarbonate (0.10 g), and bis(triphenylphosphine)palladium(II) dichloride (14 mg) were added thereto, followed by heating to reflux under a nitrogen atmosphere for 2 hours. After cooling the reaction mixture to room temperature, water and ethyl acetate were added thereto, and the insoluble substance was removed by filtration. 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 [Fuji Silysia Chemical Ltd., PSQ100B (spherical), eluent: 90-45% hexane/ethyl acetate] to obtain 0.29 g of benzyl 2-(benzyloxy)-5-(pyridin-4-yl)benzoate as a white solid.
