C–F Bond Cleavage Reactions with Beryllium, Magnesium, Gallium, Hafnium, and Thorium Halides

The work describes unexpected stoichiometric C–F bond cleavage reactions of beryllium, magnesium, gallium, hafnium and thorium halides with α,α,α ‐trifluorotoluene. The reaction of BeBr 2 / GaBr 3 or MgBr 2 / GaBr 3 mixtures as well as neat GaI 3 with α,α,α ‐trifluorotoluene in the presence of (OSi 2 Me 4 ) 2 ( I ) yields the carbenium ion containing compounds [Ph‐C(O 2 Si 2 Me 4 )][GaX 4 ] (X = Br: 1 , X = I/F: 2 ). Both compounds were successfully characterized and a defluorination type reaction under incorporation of a siloxy unit was observed. Compound 1 was also characterized by single‐crystal X‐ray diffraction analysis. The conversion of α,α,α ‐trifluorotoluene with BeI 2 , HfI 4 or ThI 4 turned out to be a halodefluorination‐type reaction with formation of α,α,α ‐triiodotoluene ( 3 ). An adequate NMR spectroscopic and the X‐ray crystallographic characterization of 3 were performed for the first time.