Nuclear magnetic resonance spectral study of β-aminoenones

Abstract

The n.m.r. spectra of the four geometrical isomers of β-aminoenones, trans-s-trans, trans-s-cis, cis-s-trans, and cis-s-cis, are discussed. It was found that the chemical shift of the α-proton of β-aminoenones depends on both anisotropic effects and the electron density: δ=δ₀–Δδ_struc=Δδ_Ar+K(q–q₀). Thus the conformation of non-rigid β-aminoenones can be determined from the observed and the calculated chemical shifts of the α-proton.