Bis(pinacolato)diboron (0.41 g), potassium acetate (0.25 g), tris(dibenzylideneacetone)dipalladium(0) (46 mg), and a 15% tricyclohexylphosphine-toluene solution (0.25 mL) were added to a dioxane (3.5 mL) solution of benzyl 2-(benzyloxy)-4-chlorobenzoate (0.35 g), followed by stirring under a nitrogen atmosphere at room temperature for 30 minutes and then at 80° C. for 5 hours and 30 minutes. After cooling the reaction mixture to room temperature, tris(dibenzylideneacetone)dipalladium(0) (46 mg) and a 15% tricyclohexylphosphine-toluene solution (0.25 mL) were added thereto, followed by stirring under a nitrogen atmosphere at 90° C. for 8 hours. After cooling the reaction mixture to room temperature, a saturated aqueous solution of sodium bicarbonate 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: 100-75% hexane/ethyl acetate] to obtain benzyl 2-(benzyloxy)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate.
