Ethyne cation radical

The generation of active radicals as a result of bond breakage makes cation-radicals useful as syn-thons. For example, arylsulfenamide cation-radicals may be used as sources of sulfenyl radicals. The reaction of 4 -nitrobenzenesulfenanilide with Lewis acids, such as BF3 and AICI3, leads to the formation of sulfonamide cation-radical. The latter appears to be an active sulfenyl transfer species. In the presence of anisol, ethenes, or ethynes, it gives phenylthiyl derivatives (Benati et al. 1990, Gross and Montevecchi 1993). 

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