Conformational Analysis and Structural Elucidation of Spirocyclic Oxaziridines Using NMR, Crystallography, and Molecular Modeling

Article abstract of DOI:10.1021/jo00129a050

The 1H NMR spectra of spirocyclic oxaziridines derived from substituted cyclohexanones and benzylamines were studied.Depending on substitution and on stereochemistry, these compounds often exhibit a substantial upfield shift of the cyclohexyl methylene or methine protons with a 1,3-diaxial relationship to the oxaziridine N-substituent.This effect is ascribed to a conformation that places an aromatic group over the plane of the cyclohexane ring.This conformation has also been found in the solid state by X-ray crystallography and is supported by molecular mechanics calculations.The use of the effect in assigning stereochemistry to this series of compounds is discussed.