48 mg of 5-bromobenzothiophene, 40 mg of sodium hydrogen carbonate, 0.6 mL of ethanol, 0.3 mL of water and 11 mg of tetrakis(triphenylphosphine)palladium(0) were added to 1.6 mL of toluene solution containing 80 mg of tert-butyl 2-(benzamido)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate at room temperature, and the resulting mixture was heated to reflux under nitrogen atmosphere for 5 hours. Ethyl acetate and water were added after the reaction mixture was cooled to room temperature. The organic layer was separated and dried over anhydrous magnesium sulfate after washed with a saturated sodium chloride aqueous solution, and the solvent was evaporated under reduced pressure. The obtained residue was purified with silica gel column chromatography [PSQ100B (spherical) manufactured by Fuji Silysia Chemical Ltd., eluent; hexane; ethyl acetate=20:1] to obtain 47 mg of tert-butyl 2-(benzamido)-4-(benzothiophen-5-yl)benzoate as white solid.
