Reactions of Bifunctional Perfluoroarylsilanes with Activated C-F Bonds in Perfluorinated Arenes.

Reactions of bifunctional perfluoroarylsilanes, p- and m-C(6)F(4)(SiMe(3))(2) as well as o-BrC(6)F(4)SiMe(3), with substituted perfluoroarenes having electron-withdrawing groups were investigated using NMR and density functional theory calculation techniques. The C-F bond in perfluoroarenes was activated by the para-position of an electron-withdrawing group, such as CF(3), C(6)F(5), CN, and NO(2). The reaction of C(6)F(4)(SiMe(3))(2) mainly occurred at the para-position of the perfluoroarenes and also occurred at the ortho-position of C(6)F(5)CN and C(6)F(5)NO(2). Two equivalent reactions of perfluoroarenes with bifunctional p- and m-C(6)F(4)(SiMe(3))(2) provided disubstituted perfluoroarenes, along with a small amount of protonated monosubstituted perfluoroarenes. The reaction of o-BrC(6)F(4)SiMe(3) with the CF(3)- and CN-substituted pentafluorobenzenes provided unexpected coupling products between C-Br and C-F bonds, in addition to the coupling products between C-SiMe(3) and C-F bonds.