The Diels-Alder reactions of a series of fluorinated trans-crotonic acids, esters, amides, an acid chloride, and an aldehyde with cyclopentadiene at 25" are discussed. The endo-exo ratios were determined by gas chromatographic and! or infrared analyses. The fluoroalkyl groups in all cases dominated the stereochemical course of the reactions, and in one series of crotonic acids the endo-exo ratios correlated very well with the inductive effects (UI) of ...
