Chiral imidazolium and triazolium salts as NHC and aNHC ligand precursors: A promising framework for asymmetric epoxidation catalysis

Abstract

Two chiral imidazolium salts and one chiral triazolium salt were synthesized containing a chiral cyclohexane bridge based on the salen ligand framework of the Jacobsen-Katsuki epoxidation catalysts. They are promising NHC and aNHC ligand precursors for asymmetric epoxidation or C–H oxidation catalyzed by organometallic compounds. The ligand framework offers plenty of opportunities for modification.

Keywords

• NHC ligands
• aNHC ligands
• Chiral ligands
• Asymmetric catalysis