Autocatalytic Friedel–Crafts Reactions of Tertiary Aliphatic Fluorides Initiated by B(C₆F₅)₃·H₂O

The C–F bond is the strongest single bond to carbon, constituting an intrinsic challenge for selective catalytic activation in the presence of other functional groups. Existing methods for the activation of tertiary aliphatic fluorides involve stoichiometric abstraction with fluorophilic Lewis acids or by Lewis-acid-catalyzed trapping with Si reagents. Herein, we describe a B­(C₆F₅)₃·H₂O-catalyzed Friedel–Crafts reaction of tertiary alkyl fluorides that proceeds rapidly at room temperature without trapping reagents. The method is completely selective for F^– over traditionally better leaving groups and displays an autocatalytic kinetic profile.