Fluoride-promoted ligand exchange in diaryliodonium salts

Authors

Bijia Wang, University of Nebraska-Lincoln
Ronald Cerny, University of Nebraska-LincolnFollow
ShriHarsha Uppaluri, University of Nebraska-Lincoln
Jayson J. Kempinger, University of Nebraska-Lincoln
Stephen G. DiMagno, University of Nebraska-LincolnFollow

Date of this Version

11-2010

Citation

Journal of Fluorine Chemistry 131:11 (November 2010), pp. 1113–1121; doi:10.1016/j.jfluchem.2010.04.004

Comments

Copyright © 2010 Elsevier B.V. Used by permission.

Abstract

Diaryliodonium salts are shown to undergo rapid, fluoride-promoted aryl exchange reactions at room temperature in acetonitrile. Aryl exchange is shown to be exquisitely sensitive to the concentration of fluoride ion in solution; fast exchange is observed as the fluoride concentration approaches a stoichiometric amount at 50 mM substrate concentration. The reaction is slowed, but not halted if benzene is the solvent, indicating that free fluoride ion or a four-coordinate anionic I(III) species may be responsible for the exchange. The fluoride-promoted aryl exchange reaction is general and allows direct measurement of the relative stabilities of diaryliodonium salts featuring different aryl substituents. The aryl exchange reaction may be of practical use for the preparation of hitherto inaccessible diaryliodonium salts, thus it also has implications for labeling radiotracers for molecular imaging with ¹⁸F-fluoride (t_1/2 = 109.7 min).