The potential energy surface of the reaction C3H5SCH2F C3H6 + FCH=S was studied at the high level of the theory (G3MP2 method) using the 6-31G(d) basis set. Barrier height is 148.63 kJ mol-1, because of the electronic effects introduced upon the Fsubstitution. It was shown F substitution in the C6-position possess two types of contribution to the calculated energy barriers and bond lengths at the transition state (TS). The first, it facilitates the TS complex formation, consequently reduces the barrier height. Secondly it reduces the H1-C2 bond length, the major component of the reaction coordinate at the TS, and increases the rate of the reaction. The G3MP2 results show the capability of this level of calculation to predict the reactivity of the intramolecular retroene reaction correctly.

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