6-Bromo-N-[2-ethyl-4-(1,1,1,2,3,3,3-heptafluoropropan-2-yl)-6-methylphenyl]-2-naphthamide (0.49 g) was dissolved in N,N-dimethylformamide (4 ml), and deaeration was carried out three times under argon atmosphere (i.e., the reaction solution was de-pressurized to 20 mmHg and brought back to atmospheric pressure under argon atmosphere). Zinc cyanide (0.07 g) and tetrakis (triphenylphosphine) palladium(0) (0.11 g) were added thereto and stirred with heating at 80° C. for 7 hours under argon atmosphere. After cooling to room temperature, the reaction solution was diluted with ethyl acetate, and washed with water and saturated brine. The organic phase was dried over anhydrous magnesium sulfate. The drying agent (anhydrous magnesium sulfate) was removed by filtration and the solvent was distilled off under the reduced pressure. The residue was purified by silica gel chromatography to obtain 6-cyano-N-[2-ethyl-4-(1,1,1,2,3,3,3-heptafluoropropan-2-yl)-6-methylphenyl]-2-naphthamide (0.04 g, yield 9%).
