To a solution of 3-methoxy-4-trifluoromethylsulfonyloxybenzoic acid methyl ester (5 g) in toluene (200 ml) is added tetrakis(triphenylphosphine)palladium (0.9 g) under argon atmosphere, and the mixture is stirred at room temperature for five minutes. To the mixture are added (2-methylphenyl)boric acid (3.2 g), lithium chloride (1.01 g) and a 2M aqueous sodium carbonate solution (11.9 ml), and the mixture is stirred at 100° C. for two hours. To the mixture is added water, and the mixture is filtered through celite to remove the palladium. The filtrate is extracted with diethyl ether, and the ether layer is washed with water, dried, and evaporated. The residue is purified by silica gel column chromatography (solvent; n-hexane→ethyl acetate:n-hexane=1:10) to give 3-methoxy-4-(2-methylphenyl)benzoic acid methyl ester (4.07 g) as oil.
