Catalytic S_N Ar Hexafluoroisopropoxylation of Aryl Chlorides and Bromides

Fluoroalkyl aryl ethers are valuable structural motifs in pharmaceuticals because compounds with these motifs are more metabolically stable and more lipophilic than their nonfluorinated analogues. However, hexafluoroisopropyl aryl ethers have not been extensively studied, presumably because of the lack of efficient synthetic methods. Herein, we describe a rhodium-catalyzed nucleophilic aromatic substitution of aryl chlorides or bromides, which act as the limiting reagents, with weakly nucleophilic hexafluoro-2-propanol under mild reaction conditions. This method provides diverse hexafluoroisopropyl aryl ethers. We demonstrated the generality of this method by carrying out reactions of a large array of unactivated aryl halides, and we found that the success of the reactions relied on arene activation by means of η⁶ -coordination.