AbstractThe13C NMR spectra of eleven 3‐N,N‐dialkylamino‐5,5‐dimethylcyclohex‐2‐en‐1‐ones have been determined. The chemical shifts of the three sp2carbons and of the two methylene carbons on the cyclohexenone moiety have been subjected to factor analysis. Two factors are necessary and sufficient to account for more than 93% of the total variance. The more important axis (79%) corresponds to a factor closely related to the inductive and steric effects of the alkyl nitrogen substituents. The second parameter is more difficult to interpret and could correspond to the ‘ipsoeffects