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.