Detailed
kinetic profiles of the copper-catalyzed exchange between
the acetylenic proton and iodide of terminal and 1-iodophenylacetylenes
are reported. The electronic nature of the alkynes does not influence
the equilibrium of the exchange (K
eq =
1), only the rate of equilibration. Notably, the profiles are the
same for electron-rich, methyl-substituted phenylacetylenes but are
divergent for electron-deficient, trifluoromethyl-substituted variants.
The heretofore unreported exchange process yields practical considerations
regarding reactions involving iodo and terminal alkynes.