Inductive constants for the cyclohexenyl, cyclohexenylmethyl, cyclopentenyl, and cyclopentenylmethyl groups

Abstract

In connection with a study of neighbouring double bond participation in cyclopentenylalkyl and cyclohexenylalkyl systems, Taft's σ* constants were determined for cyclopent-1-, -2-, and -3-enyl, cyclopent-1-, -2-, and -3-enylmethyl, cyclohex-1-enyl, and cyclohex-1-, -2-, and -3-enylmethyl groups as well as for the corresponding saturated substituents which have not been reported before. It was shown that the presence of the double bond significantly affects the polar characteristics of the group and that this effect depends on its position in the ring. The negative values for cyclohex-1-enyl and cyclopent-1-enyl groups do not agree with the electron-withdrawing effect of αβ-unsaturated substituents in open chain systems.