Gas‐phase fluorine migration reactions in the radical cations of pentafluorosulfanylbenzene (Aryl―SF 5 ) and benzenesulfonyl fluoride (Aryl―SO 2 F) derivatives and in the 2,5‐xylylfluoroiodonium ion

The gas‐phase reactions of Aryl―SF 5 ·+ and Aryl―SO 2 F ·+ have been studied with the electron ionization tandem mass spectrometry. Such reactions involve F‐atom migration from the S‐atom to the aryl group affording the product ion Aryl―F ·+ by subsequent expulsion of SF 4 or SO 2 , respectively. Especially, the 4‐pentafluorosulfanylphenyl cation 4‐SF 5 C 6 H 4 + ( m / z 203) from 4‐NO 2 C 6 H 4 SF 5 ·+ by loss of ·NO 2 could occur multiple F‐atom migration reactions to the product ion C 6 H 4 F 3 + ( m / z 133) by loss of SF 2 in the MS/MS process. The gas‐phase reactions of 2,5‐xylylfluoroiodonium ( p Xyl―I + F, m / z 251) have also been studied using the electrospray tandem mass spectrometry, which involve a similar F‐atom migration process from the I‐atom to the aryl group giving the radical cation of 2‐fluoro‐ p ‐xylene (or its isomer 4‐fluoro‐ m ‐xylene, m / z 124) by reductive elimination of an iodine atom. All these gas‐phase F‐atom migration reactions from the heteroatom to the aryl group led to the aryl―F coupling product ions with a new formed C Aryl ―F bond. Density functional theory calculations were performed to shed light on the mechanisms of these reactions. Copyright © 2014 John Wiley & Sons, Ltd.