Influence of the introduction of fluorine atoms on the C-13 NMR spectra ofacrylic esters

The effect of progressive introduction of fluorine atoms on the C-13 chemic al shifts in the beta,beta-dimethylacrylic ester series is examined. The ma in perturbation is located at the olefinic carbons positions. Comparison of the various data allows the calculation of increments corresponding to the substitution of methyl groups by CH2F, CHF2 or CF3 groups. The perturbatio n induced on the vinylic carbons increases roughly with the number of fluor ine atoms. However, an influence of the stereochemistry is observed in the CH2F and CF3 series. The increments are not additive for compounds bearing two highly fluorinated groups at the beta-positions. Copyright (C) 1999 Joh n Wiley & Sons, Ltd.