4-Chlorophenethyl tosylate (683 mg, 2.20 mmol), sodium carbonate (236 mg, 2.20 mmol) and sodium iodide (20 mg, 0.13 mmol) were added to a solution of (S)-3-(4-nitrobenzoyloxy)pyrrolidine (472 mg, 2.00 mmol) in acetonitrile (10 ml), and they were heated under reflux at 90° C. for 8 hours. The solvent was evaporated under reduced pressure. The obtained residue was subjected to silica gel column chromatography. The product was eluted with hexane and ethyl acetate (10:1) and then with a mixture of the same solvents (1:1). The appropriate fractions were combined, and the solvent was evaporated under reduced pressure to obtain (S)-1-(4-chlorophenethyl)-3-(4-nitrobenzoyloxy)pyrrolidine in the form of a light yellow oil (315 mg, 42%).
