Dehydroxy-Perfluoro-tert-butylation of alcohols with PhSO2C(CF3)3 and insights into the structure of the [C(CF3)3]− anion

Branched PFOA and PFOS have shorter half-lives, lower toxicity, and weaker serum protein binding than linear ones, offering better environmental and health safety. Yet methods to access such branched motifs remain under developed. We now introduce a one-step dehydroxy-perfluoro-tert-butylation of alcohols, in which perfluoro-tert-butyl phenyl sulfone serves both to activate the C-O bond and to deliver the perfluoro-tert-butyl group. Mechanistic studies-including DFT calculations-reveal that perfluoro-tert-butyl phenyl sulfone first generates perfluoroisobutylene in situ to effect C-O bond cleavage, after which a catalytic iodide engages in the C-C bond-forming event. Remarkably, the isolated perfluoro-tert-butyl anion salt, characterized by single-crystal X-ray diffraction, displays significant negative hyperconjugation, as evidenced by the elongated C-F bonds. This operationally simple protocol tolerates a wide array of functional groups and complex substrates, providing rapid access to branched perfluoroalkyl scaffolds with broad implications for drug discovery and advanced materials.