Reactive Dications: The Superacid-Catalyzed Reactions of Alkynes Bearing Adjacent <i>N</i>-Heterocycles or Amine Groups

Abstract

A variety of aminoalkynes and related heterocycles are reacted in the Bronsted superacid CF(3)SO(3)H (triflic acid), and products are obtained in generally good yields (69-99%) from Friedel-Crafts-type reactions. The reactions are consistent with the formation of novel dicationic intermediates having a vinyl cationic site and an adjacent protonated N-heterocycle or ammonium cation.