C−H Functionalization of Organic Cations: An Interesting and Young Journey
Organic ionic compounds, especially for those with organic cations, are commonly applied to ionic liquids (ILs), organocatalysts, (a)NHC ligands, ion recognition, and optoelectronic materials. Direct C−H functionalization of organic cations offers a valuable opportunity for rapid assembly of diverse functionalized cations and further exploitation of their applications in material sciences. This review summarizes the substantial progress in C−H functionalization of organic cations from 1960s to May 2020, involving transition metal-mediated/catalyzed C−H alkylation, arylation, and annulation, and photo-induced C−H functionalization. The substrate scope, limitation, regio-/chemoselectivity, and reaction mechanism are discussed. In addition, the applications of some new organic functional materials are briefly exemplified. This review also aims to remind readers that much care should be taken when using an organic ionic compound as the solvent, because it can behave as a reactant to break desired coupling reaction.
- This article is part of the themed collection: Synthetic methodology in OBC