Theoretical studies of the Diels-Alder reaction of 1-fluoroethylene with some model dienes

The effect of fluorine substitution on TS formation has been estimated. Theoretical investigation has led to the conclusion, that the introduction of one electron-withdrawing substituent (fluorine atom) into dienophile molecule makes the process of reaching the TS more difficult due to an increase in the 'energy of concert' (ΔGact0) compared to non-fluorinated system. The substitution of fluorine for hydrogen in exocyclic vinyl group results (with one exception) in a lower activation energy and higher energy gain of reaction for systems with 1-fluoroethylene.