Anomeric effect in N-azidomethylpyrrolidine: gas-phase electron diffraction and theoretical study

Abstract

Gas-phase electron-diffraction data and high-level quantum chemical calculations have been used to study the conformational behaviour of N-azidomethylpyrrolidine. The two most stable conformers with a relative abundance of about 80% at 298 K possess gauche orientation of the azidomethyl group around the C–N_pyr bond (C–N_azidogauche with respect to the endocyclic N_pyr–C bond). This orientation is a strong manifestation of an anomeric effect. The influence of the anomeric effect is also reflected in shortening of the C–N_pyr bond and lengthening of the C–N_azido bond as compared to such bonds in other compounds.