N-acyloxaziridines: characterization of both nitrogen inversion and N–C(O) bond rotation in an amido system

Variable temperature 13C NMR investigations reveal that the N-acyl oxaziridine system can exhibit two independent stereodynamic processes: nitrogen inversion becomes slow on the NMR timescale at ca.–20 °C (ΔG‡ 10.9–11.9 kcal mol–1) and at ca.–60 °C rotation about the N–C(O) bond also becomes slow (ΔG‡ 10.2 kcal mol–1).