Résonance Magnétique Nucléaire de 17 O. Aldéhydes et cétones aliphatiques: additivité des effets de substitution et corrélation avec la 13 C‐RMN

17 O‐NMR. Aliphatic aldehydes and ketones, additivity of substituent effects and correlation with 13 C‐NMR. The 17 O‐chemical shifts of 9 aldehydes, 22 aliphatic and 4 alicyclic ketones, in the natural abundance FT.‐NMR. spectra followed a good correlation with the 13 C‐chemical shifts of the terminal C‐atoms of corresponding methylene compounds. An additivity relation involving 6 parameters represents the 17 O‐shifts of 28 of the measured products with a standard deviation of 2.5 ppm. The additivity parameters are discussed with respect to the modifications of the polarity of the carbonyl group induced by the hyperconjugative interaction of π and π* orbitals with the π CH 3 orbitals of the alkyl substituent groups.