A solution was prepared from tert-butyl 3-(methylsulfonyloxy)pyrrolidine-1-carboxylate (2.65 g, 10 mmol) and sodium cyanide (2.5 g, 50 mmol) in N,N-dimethylformamide (100 mL). The reaction mixture was stirred at 100°C for 16 hours. After completion of the reaction, it was cooled to room temperature and the reaction mixture was poured into water and extracted with ethyl acetate. The organic phases were combined, washed sequentially with water and saturated saline and dried over anhydrous sodium sulfate. After filtration, the organic phase was concentrated under reduced pressure and the resulting residue was purified by column chromatography (eluent: petroleum ether/ethyl acetate=5:1) to afford 1-N-Boc-3-cyanopyrrolidine (1.92 g, 98% yield).
