Synthesis
General procedure for the synthesis of tert-butyl (R)-3-cyanopiperidine-1-carboxylate from tert-butyl (R)-3-carbamoylpiperidine-1-carboxylate: under nitrogen protection, phosphorochloride (203 μL, 2.18 mmol) was slowly added dropwise to a solution of tert-butyl (R)-3-carbamoylpiperidine-1-carboxylate (0.5 g, 2.18 mmol) in pyridine (10 mL) in pyridine (10 mL) at a reaction temperature of 0 °C. The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, it was diluted with ethyl acetate and washed twice with 10% hydrochloric acid solution. The organic and aqueous phases were separated and the organic phase was dried over anhydrous sodium sulfate and subsequently concentrated to dryness under reduced pressure. The resulting tert-butyl (R)-3-cyanopiperidine-1-carboxylate did not require further purification and could be used directly in the next step of the reaction. Yield: quantitative; LCMS (T): 4.48 min (Method A); MS (ES+) m/z: 211.1.
