Synthese und 13C-NMR-Spektren tert-butylierter Cyclohexenon-Epoxide Synthesis and 13C NMR Spectra of tert-Butylated Cyclohexenone Epoxides

Abstract

Abstract NMR spectra of several cyclohexenone epoxides obtained by oxygenation of 4-R-2,6-di-tert-butylphenols have been assigned, using substituent induced shifts, offresonance and C - H single-frequency-decoupling techniques, as well as completely C - H coupled spectra. For the -butyl signals the following sequence rules are relevant: methyl carbons and protons = δtBu-C-olefinic(sp2) > δtBu-C-oxirane(sp3) ≥ δtBu-C-OH(sp3); quaternary carbons = δtBu-C-OH(sp3) > δtBu-C-olefinic(sp2) > δtBu-C-oxirane(sp3). In these compounds, the oxirane oxygen causes a highfield shift of the signal of the quaternary C-atom of the feri-butyl group as compared with the influence of a hydroxy group.