General procedure for the synthesis of 3-oxocyclopentanecarbonitrile from 2-cyclopentenone: a mixed solution of 2-cyclopentenone (10 g, 122 mmol), potassium cyanide (9.5 g, 146 mmol), and triethylamine hydrochloride (25 g, 83 mmol) in methanol (150 mL) was stirred for 4 hours at room temperature. Upon completion of the reaction, the reaction mixture was concentrated; the residue was redissolved in ethyl acetate. The resulting solution was washed sequentially with water and saturated saline, dried over anhydrous sodium sulfate and concentrated. The residue was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1) to give 7.5 g of 3-oxocyclopentanecarbonitrile.1H NMR (400 MHz, CDCl3): δ 3.13-3.51 (m, 1H), 2.56-2.63 (m, 1H), 2.16-2.48 (m, 5H).
