228857-58-7

24424-99-5

7729-30-8

228857-58-7

To a mixed solution of (R)-azetidine-2-carboxylic acid (20 g, 200 mmol), water (200 mL) and dioxane (200 mL) was slowly added dropwise a solution of di-tert-butyl dicarbonate (Boc2O) in dioxane (100 mL) at 0 °C. After the dropwise addition was completed, the reaction mixture was stirred at room temperature for 1 hour. After the reaction was complete, the mixture was concentrated and ether (200 mL) and water (200 mL) were added to the residue. The aqueous layer was acidified to pH 3-4 with 2N hydrochloric acid and then extracted with ethyl acetate (200 mL). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated to give (R)-N-BOC-azetidine-2-carboxylic acid (40 g) in quantitative yield.LRMS (M-100 + H*) m/z 102.1.