Author: Vogeli, U.; von Philipsborn, W.
Description: Vicinal C,H spin coupling (3JC,H) in substituted alkenes has been investigated systematically. Emphasis is laid on the stereochemical significance (Jtrans/Jcis) and on the various structural factors which influence 3JC,H, such as π-bond order, torsional angle ϕ, bond angle θ, electronegativity of substituents and steric effects. A new type of γ-effect is observed in 3JtransC,H which appears to have the same origin as the γ-shift effect. By comparison of 3Jmath image and 3JH,H, it was found that the relation 3JC,H ≈︁ 0·6 3JH,H holds for both trans and cis coupling constants. Finally, it is concluded that 3JC,H constitutes a valuable criterion to distinguish E- and Z-isomers, particularly in trisubstituted alkenes. Applications to natural products are presented.
Subject headings: Vicinal; Spin coupling; Alkenes
Publication year: 1975
Journal or book title: Organic Magnetic Resonance
Volume: 7
Issue: 12
Pages: 617-627
Find the full text : https://onlinelibrary.wiley.com/doi/abs/10.1002/mrc.1270071213
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Type: Journal Article
Serial number: 1898