General procedure for the synthesis of tert-butyl 3-acetoxyazetidine-1-carboxylate from ethanoic anhydride and N-Boc-3-hydroxyazetidine: 0.27 g (1.559 mmol) of N-Boc-3-hydroxyazetidine, 0.61 g (4.677 mmol) of diisopropylethylamine and a catalytic amount of 4-dimethylaminopyridine were dissolved at 0 °C in 7 mL of dichloromethane in dichloromethane. To this solution 0.32 g (2 mmol) of acetic anhydride was slowly added, followed by stirring the reaction for 16 hours at room temperature. After completion of the reaction, the solvent was removed by vacuum distillation. The crude product was purified by column chromatography using a mixed solvent system of hexane and ethyl acetate (3:1, v/v) to give 0.33 g (98% yield) of tert-butyl 3-acetoxyazetidine-1-carboxylate. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 5.12 (1H, m), 4.23 (2H, dd), 4.12 (2H, dd), 2.09 (3H, s), 1.44 (9H, s).
