Generation and Reactivity of 1-Imidocarbenium Cations in the Friedel–Crafts-type Reaction

Abstract

Herein, we discuss the formation and reactivity of 1-imidocarbenium cations in Friedel–Crafts-type reaction between 1-imidoalkylphosphonium salts and arenes. The observed weakening of C α –P + bond is described qualitatively and quantitatively. The determination of rate constants and activation energies of C α –P + bond cleavage enabled systematic reactivity investigations of a series of phosphonium salts with different structures. Finally, the application scope for the imidoalkylation of aromatic hydrocarbons was explored. The results confirm that the generated 1-imidocarbenium cations are reactive enough to alkylate strongly activated, less-activated, or even inactivated aromatic compounds.