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17 O NMR spectra and conformation of cyclic vinyl ethers
Author(s) -
Taskinen Esko,
Ora Mikko
Publication year - 1995
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260330402
Subject(s) - chemistry , moiety , ring (chemistry) , nmr spectra database , chemical shift , nuclear magnetic resonance spectroscopy , spectral line , carbon 13 nmr , stereochemistry , proton nmr , ring size , crystallography , computational chemistry , organic chemistry , physics , astronomy
The 17 O NMR spectra of a number of heterocyclic vinyl ethers were recorded in CDCl 3 and DMSO‐ d 6 solutions. The oxygen chemical shifts reveal substantial differences in the strength of p‐π conjugation between the five‐ and six‐membered ring compounds, especially between those with an exocyclic CC bond. The conformations of the title compounds were estimated by force‐field calculations; the calculated torsional angle of the COCC moiety appears to be a linear function of the 17 O NMR shift data, corrected by appropriate structural factors.