Carbon-Fluorine Reductive Elimination from a High-Valent Palladium

Aryl fluorides are valuable compounds as pharmaceuticals1 and as tracers for positron-emission tomography.2 The general synthesis of complex, highly functionalized aryl fluorides in which the carbon-fluorine bond is introduced at a late stage of the synthesis is a challenge unmet by conventional fluorination methods. We recently communicated that aryl boronic acids can be converted into aryl fluorides via reaction of stoichiometric aryl palladium complexes with the electrophilic fluorination reagent Selectfluor3 (1) (eq 1).4 Two potential mechanisms for carbon-fluorine bond formation are palladium-carbon bond cleavage by the electrophilic fluorination reagent and oxidation of the palladium center to form a discrete high-valent palladium fluoride followed by reductive elimination to form a carbon-fluorine bond. In this Communication we present the carbon-fluorine bond formation from two high-valent aryl palladium fluoride complexes. The observation of high