Iodine atom-catalysed isomerization of cis-cinnamic esters: polar effect of the ester group

Abstract

The measurements of rate constants for iodine atom-catalysed isomerization of alkyl cis-cinnamates, already mentioned in the literature, have been extended to a series of esters containing electron-attracting residues in the ester group. It appears that the rate constants depend on the polar effect rather than on the size of the ester function. A linear relationship is found between log k for isomerization and Taft's substituent constants (σ*) providing a small negative ρ* value.