Nucleophilic Vinylic Substitution and Vinyl Cation Intermediates in the Reactions of Vinyl Iodonium Salts

Abstract

Publisher Summary This chapter discusses the concerted-dissociative part of the mechanistic spectrum, mainly on the basis of recent results obtained in the study of reactions of vinyl iodonium salts. Also, photochemical dissociative reactions generating vinyl cations have been discussed and compared with the corresponding thermal reactions. Vinyl cations are admittedly unstable species in both thermodynamic and kinetic terms and are recognized as reactive intermediates. Most recently, a new family of compounds, vinyl iodonium salts, allowed the study of simpler, less stabilized vinylic cations. The parent vinyl cations are very unstable both thermodynamically and kinetically, and can only be generated under forced conditions in solution. The chapter discusses photoexcitation of appropriate precursors that generates primary vinyl cations. Vinyl(aryl) iodonium salts are good electrophiles carrying an excellent nucleofuge, an iodoarene, which makes them good substrates for nucleophilic substitution as well as versatile precursors for vinyl cations.