Halogenated Trityl Cations as Easy-to-Access Super Electrophiles

Herein, we present the easy-to-access synthesis of the perfluorotrityl cation (15F⁺) with commercial GaCl₃ and the further functionalization of the para-fluorine atoms of 15F⁺ via halodefluorination using trimethylsilyl halides TMSX (X=Cl, Br). This gives access to equally reactive halogenated trityl derivatives (p-3Cl12F⁺ and p-3Br12F⁺), which can be handled at room temperature. The impact of the para-exchange on the electronic structure is determined by NMR and UV/Vis spectroscopy. Finally, the new synthons' high hydride ion affinities are demonstrated computationally and experimentally by hydride abstraction from the short-chain, linear alkanes n-pentane and n-butane.