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The 1 H NMR spectra of exo ‐ and endo ‐3‐thiatricylo[4.2.1.0 2,5 ]non‐7‐ene 3,3‐dioxide. The shielding effect of the sulfone group
Author(s) -
Martin H.D.,
Iden R.,
Scheutzow D.,
Jackman L. M.
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270140309
Subject(s) - norbornene , sulfone , ene reaction , chemistry , coupling constant , proton , spectral line , nmr spectra database , proton nmr , crystallography , stereochemistry , medicinal chemistry , polymer chemistry , organic chemistry , physics , polymer , monomer , particle physics , quantum mechanics , astronomy
The proton spectra of exo ‐ and endo ‐3‐thiatricyclo[4.2.1.0 2,5 ]non‐7‐ene 3,3‐dioxide have been analysed and completely assigned. Considerations of coupling constants indicate that the thietane ring is nonplanar and that the norbornene residue is significantly distorted from the geometry of norbornene itself. The sulfone group induces significant changes in the shielding of the proximate olefinic proton in the endo isomer and the bridge protons in the exo isomer. These shifts appear to be the result of the electrostatic effects and effects associated with the diagmagnetic anisotropy of the sulfone group.