A computational insight into cyclopropenone activated dehydration reaction of alcohols

The cyclopropenone activated dehydration reaction of alcohols is a promising alternative to alcohol substitution reactions to avoid hazardous byproducts and harsh reaction conditions. Density functional theory calculations at M062X/6-31+G(d,p) level were performed for two proposed reaction mechanisms of the cyclopropenone activated chlorodehydration reaction where alkyl chloride product can be obtained from both of the proposed reaction mechanisms but chloroxalate has only one alternative. The calculations enabled us to explain the rection mechanisms in detail. Additionally, the effects of the various substituents on the cyclopropenone ring for the product distribution ratio was clarified.The substitution with electron donating group on para position of the phenyl ring of cyclopropenone has no effect on the relative free energy of the rate-determining step where the electron-withdrawing group increase the energy values independent from the position. The product ratio values that were calculated from energy barriers are in harmony with the experimentally obtained ones pointing out the reaction mechanism preference.