Ruthenium(II) complexes with chelating n-heterocyclic carbenes and a ruthenate(II) complex as catalysts for the anti-Markovnikov hydroaminations of styrene

Abstract

New ruthenium chelate and ruthenate complexes were synthesized through the reaction of benzimidazolium salts and [RuCl2(p-cymene)]2 in toluene and characterized by elemental analysis, 1H NMR and 13C NMR spectroscopy. These ruthenium complexes were tested as catalysts in the intermolecular hydroamination reactions between styrene with aromatic amines in ionic liquid. All of these complexes tested here showed good catalytic activity in these reactions. The hydroamination reactions regioselectively produced anti-Markovnikov addition products in moderate to good yields by using 1 mol% of the ruthenium complex. © 2021 The Japan Institute of Heterocyclic Chemistry.