Polyene acids. Part X. The conformation of hexenolactone and the configuration of the derived sorbic acid as indicated by proton magnetic resonance spectroscopy

Abstract

The first order spectrum of hex-2-eno-δ-lactone at 60 Mc./sec. shows that only one conformation, that with the methyl group pseudo-equatorial, is present at 40°. The low-melting sorbic acid derived by ring-opening of the lactone with methoxide is shown to be homogeneous and to be the cis-αβ-trans-γδ-isomer. Chemical shifts and coupling constants are given, also, for methyl all-trans-sorbate.