Triple Regioselective Functionalization of Cationic [4]Helicenes via Iridium-Catalyzed Borylation and Suzuki Cross-Coupling Reactivity

Chemistry. 2022 Oct 7;28(56):e202201853. doi: 10.1002/chem.202201853. Epub 2022 Aug 18.

Abstract

In essentially one-pot, using Ir- and Pd-catalysis, tris(arene)-functionalized cationic [4]helicenes are synthesized with full regioselectivity and enantiospecificity starting from a trivial precursor (17 examples). This poly-addition of aryl groups improves key optical properties, that is, fluorescence quantum yields and lifetimes. Electronic circular dichroism and circularly polarized luminescence signatures are observed up to the far-red domain, in particular with additional arenes prone to aggregation.

Keywords: Ir-catalyzed borylation •late stage functionalization; cationic helicenes; chiroptical spectroscopy; dyes and fluorophores.