Regioselectivity control with enolate anions

As mentioned on p. 99, gas-phase reactions are under charge control and, therefore, almost by definition, FO theory is inappropriate for their study. Such a conclusion would be precipitous. Note to begin with that only the anion behaves in an unusual manner, the comportment of its partner being normal. An FO study of gas-phase SN2 reactions (X- + RY —> XR + Y ) is therefore perfectly possible. We can also study the competition of electrophilic sites. On the other hand, FO theory will give questionable conclusions for the regioselectivity of anions (e.g. O-alkylation versus C-alkylation of enolates). For these problems, a more thorough study, requiring in particular transition states determination, is necessary. 

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