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Long‐range proton‐proton interactions through epoxides
Author(s) -
JosephNathan P.,
Díaz E.
Publication year - 1971
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.1270030205
Subject(s) - proton , allylic rearrangement , range (aeronautics) , spectral line , chemistry , irradiation , carbon fibers , double bond , resolution (logic) , asymmetric carbon , stereochemistry , crystallography , materials science , physics , organic chemistry , nuclear physics , optically active , composite number , astronomy , artificial intelligence , computer science , composite material , catalysis
Double and triple nuclear magnetic resonance experiments performed at 100 MHz demonstrate the existence of long range 1 H— 1 H couplings through epoxides. In a series of epoxycontaining sesquiterpenoids, interactions between protons separated by up to six sigma bonds were detected. These interactions may have origins similar to the well‐known allylic and homoallylic couplings found in carbon‐carbon double bonded compounds, although they are much smaller in the epoxy systems. We propose to name them as ‘epoallylic’ and ‘epohomoallylic’ interactions. Some couplings are observed directly, whereas in other cases only an improvement in resolution is seen during multiple irradiation experiments. Even in these latter cases the areas of the observed peak do not change upon multiple irradiation which demonstrates the absence of nuclear Overhauser effects. The stereochemistry of some asymmetric centers of the compounds studied is deduced from the spectra.