Theoretical study on the mechanism of selective fluorination of aromatic compounds with Selectfluor

The selective fluorination of aromatic compounds with Selectfluor has been studied theoretically. The structural and energetic features of pi complexes of substituted benzenes with Selectfluor are investigated, and the fluorine bond (F center dot center dot center dot pi) has been found to make an important contribution to the stabilization of the p complexes. Our calculations indicate that the SET mechanism, which involves one electron transfer from the aromatic substrate (D) to Selectfluor (A), is preferred over the S(N)2 mechanism. The analysis of the minimum energy path (MEP) suggests that the DABCO moiety of Selectfluor seems to take an active role in the fluorination of aromatic compounds with Selectfluor. In addition, a two-state model analysis, as well as the characteristics of avoiding crossing between the DA and D(+)A(-) states of benzene/Selectfluor are addressed to obtain deep insight into the features of the SET mechanism.