General procedure for the synthesis of ethyl 1-benzylpyrrolidine-3-carboxylate from ethanol and 1-benzylpyrrolidine-3-carbonitrile: A solution of 1-benzylpyrrolidine-3-carbonitrile (1.5 g, 7.9 mmol) in ethanol (40 mL) was treated with a dioxane solution (20 mL) in 4 M HCl and stirred overnight at room temperature. Upon completion of the reaction, the reaction mixture was cooled to 0 °C and the pH was adjusted to neutral with saturated aqueous NaHCO3 solution, followed by extraction with ethyl acetate (EtOAc). The organic layers were combined, dried with anhydrous Na2SO4 and concentrated under reduced pressure. Purification by fast column chromatography (eluent: 35-50% EtOAc/hexane) afforded ethyl 1-benzylpyrrolidine-3-carboxylate (1.1 g, 58% yield).
