17O NMR chemical shifts versus structure relationships in oxiranes

✍ Scribed by Hiizu Iwamura; Tadashi Sugawara; Yuzo Kawada; Kazuo Tori; Ryonosuke Muneyuki; Ryoji Noyori

• Book ID: 104246429
• Publisher: Elsevier Science
• Year: 1979
• Tongue: French
• Weight: 249 KB
• Volume: 20
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)95432-2

✦ Synopsis

Natural-abundance 17 0 NMR spectra have been measured for twenty one oxiranes. Their chemical shifts covering a 100 ppm range were interpreted in terms of the paramagnetic S-and diamagnetic y-effects. In addition, throughspace orbital interaction between the ethylenic II and the Walsh orbitals of the oxirane ring was suggested by a lowfield shift in norbornadiene exo-oxide. We have shown that natural-abundance 17 0 NMR spectroscopy which is now easily accessible by chemists as a result of recent advances in FT NMR instrumentation can be extremely useful for elucidating the structure and chemical bonding of oxygen-containing compounds. Chemical shifts covering a more than 1000 ppm range are explained in terms of empirical rules which are in principle quite similar to those used to interpret 13C NMR data.' In order to demonstrate the usefulness of 17 0 NMR as a structural probe of more subtle changes in structure and chemical bonding, we have now examined a series of oxiranes. 3 Just as in 'H and 13 C NMR of cyclopropanes, oxiranes, and aziridines, the oxygen nuclei of oxiranes are most highly shielded among the ether family.