NMR-Untersuchungen an Dicyclopentadien-Derivaten. VII. Zur Abhängigkeit des γ-gauche Effektes von der sterischen Kompression eng benachbarter Protonen bei exo/endo-Isomerieumkehr

N.M.R. Investigations of Dicyclopentadiene Derivatives. VII. Dependence of the γ-Gauche Effect on the Steric Compression of Closely Neighbouring Protons during the Reversal of Exo/Endo-Isomerism The ¹³C-chemical shifts of the carbon atoms C¹, C⁶, C⁷, C⁸ and C¹⁰ of different substituted exo/endo-isomeric dicyclopentadiene derivatives are highly depending on the configuration of these compounds. The observed shift effects are discussed within the concept of the steric γ-gauche effect and are not only explained by nonbonding interactions of steric closely neighbouring protons.