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Electronic effects in some 3‐substituted‐2‐cyclohexenones: A study by carbon‐13 n.m.r. spectroscopy
Author(s) -
Bedford G. R.,
Taylor P. J.
Publication year - 1977
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.1270090110
Subject(s) - electronegativity , carbon fibers , resonance (particle physics) , chemistry , spectral line , spectroscopy , chemical shift , computational chemistry , stereochemistry , organic chemistry , materials science , physics , atomic physics , quantum mechanics , astronomy , composite number , composite material
The carbon‐13 n.m.r. spectra of some 3‐substituted‐2‐cyclohexenones show very wide variations in chemical shift at C‐3 that correlate with Pauling electronegativity χ, even wider variations at C‐2 that correlate with the Taft resonance parameter σ R º and almost no variation at C‐1. These very different effects are shown to be consistent with the electronic distribution for these and related compounds revealed by other spectroscopic techniques. Reasons for the insensitivity of carbon‐13 n.m.r. to configurational and conformational variation in simple enamino‐ketones are discussed.