Anion‐Dependent Imidazolium‐Based Catalysts for Allylation of Aniline with Tunable Regioselectivity

Abstract

Metal‐free catalysts based on 1,3‐bis(carboxymethyl)imidazolium halides mediate the reaction between allylic alcohols and anilines, providing the corresponding N ‐, 2‐ and 4‐allylaniline isomers selectively. The imidazolium counterion plays a crucial role in the outcome of the reaction. Thus, while the imidazolium chloride selectively provides the N ‐substituted aniline, the bromide and iodide imidazolium salts produce the 2‐ and 4‐allylaniline isomers, respectively, with excellent selectivities. A set of complementary catalysts, which are available by simple modulation, is here presented to conduct a highly regioselective allylation reaction of anilines. Not only the catalysts are synthesized in a straightforward and easily scalable manner, but they can be recycled and used under solvent‐free reaction condition, due to the favorable interactions with the reactants.