Photoredox-Cobaloxime Catalysis for Selective Oxidative Dehydrogenative [4+2] Annulation of Imidazo-Fused Heterocycles with Alkenes
Ailong Shao, Yuanyuan Li, Yuxue Ding, Yahui Li, Shulian Wu, Yuan Jiang, Min Dong, Hai Wu, Shui-Sheng Chen
Abstract
A selective oxidative [4+2] annulation of alkenes with imidazo-fused heterocycles has been developed by using the synergistic combination of photoredox and cobaloxime catalysts. It allows facile access to various imidazole-fused polyaromatic scaffolds accompanied by H 2 evolution. This protocol features high regioselectivity as well as a broad substrate scope. Detailed mechanistic studies indicate that twice the electron/H transfer processes facilitated by this catalytic system achieve the annulation π-extension of imidazo-fused heterocycles with alkenes.
Topics & Concepts
AnnulationChemistryRegioselectivityCatalysisPhotoredox catalysisCombinatorial chemistryOxidative phosphorylationImidazoleSubstrate (aquarium)PhotochemistryOrganic chemistryPhotocatalysisGeologyOceanographyBiochemistryCatalytic C–H Functionalization MethodsRadical Photochemical ReactionsSulfur-Based Synthesis Techniques