Water → 4-(5-Chloropentanoyl)benzonitrile

1 g (6.9 mmol) of 4-acetylbenzonitrile was dissolved in 8 ml of tetrahydrofuran. 9 ml of lithium bis(trimethylsilyl)amide (1 M solution in hexane) was gradually added to the solution at −70° C. and they were stirred for 30 minutes. 1.43 g (7 mmol) of 1-chloro-3-iodopropane dissolved in 6 ml of tetrahydrofuran was added thereto, and the resultant mixture was stirred at room temperature overnight. The reaction liquid was poured into water. After the extraction with ethyl acetate, the extract was washed with 1 N hydrochloric acid and saturated aqueous common salt solution, and then dried over powdery magnesium sulfate. The solvent was evaporated, and the residue was purified by the silica gel chromatography to obtain the title compound.