Catalytic olefination. Estimation of the reactivity of polyhaloalkanes

Global electrophilicity indices and carbon-halogen bond energies of a wide series of halogen derivatives were calculated in terms of the density functional theory (DFT). The calculated values were used to estimate the reactivity of halogen derivatives under conditions of catalytic olefination. Reactions of N-unsubstituted hydrazones with polyhaloalkanes in the presence of CuCl afforded substituted alkenes. The relation between the structure of polyhaloalkanes and their reactivity was studied using the reaction with 4-chlorobenzaldehyde hydrazone as an example. It was found that increase in the global electrophilicity index and decrease in the C-Hlg bond energy are accompanied by increase in the “olefinating” power of halogen derivatives.