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Studies on olefins. IX—proton NMR study of some CH 2 CR 1 R 2 and CHR 3 CR 1 R 2 alkenes
Author(s) -
Rummens Frans H. A.,
Lomas John S.,
Tiffon Bernard,
Coupry Claude,
LumbrosoBader Nicole
Publication year - 1982
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.1270190110
Subject(s) - coupling constant , chemistry , propene , proton , allylic rearrangement , chemical shift , spectral line , nmr spectra database , coupling (piping) , computational chemistry , analytical chemistry (journal) , physics , organic chemistry , materials science , nuclear physics , catalysis , particle physics , astronomy , metallurgy
The proton NMR spectra of 2,3,4,4‐tetramethyl‐3‐t‐butylpent‐1‐ene rotarners have been completely assigned by low temperature NOE measurements. Chemical shifts and cis and trans allylic coupling constants are unambiguously determined. It is shown that other 2‐substituted propenes can be assigned on the basis of the coupling constants, but not from the chemical shift data. In 1,2‐disubstituited propenes, however, the transoid coupling constant falls in the range of the cisoid coupling constant values of the 2‐substituted propenes. Coupling constants cannot, therefore, be used in the 1,2‐disubstituted propene series as a criterion for determining structure.