Scope and Limitations of the Base-Free Copper(I) Oxide Catalyzed<i>N</i>-Heteroarylation of 1<i>H</i>-(Benz)imidazoles with<i>B</i>-Heteroarylboronic Acids or 2-Heteroaryl-4,4,5,5-tetramethyl-1,3,2-dioxaborolanes
作者:Agathe Begouin、Maria-João R. P. Queiroz
DOI:10.1002/hlca.201200310
日期:2013.5
copper(I) oxide catalyzed N‐arylation reaction performed in MeOH at room temperature for the synthesis of N‐substituted azoles and amines was extended to the heterocyclic series, i.e., we report herein the base‐free copper(I) oxide catalyzed N‐heteroarylation of 1H‐(benz)imidazole, by means of electron‐rich or electron‐deficient B‐heteroarylboronic acids or 2‐heteroaryl‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolanes
A series of cationic π-extended imidazolium salts were synthesized by a sequential Cu-catalyzed arylation/annulation and photocyclization strategy in a simple but efficient way. Among them, a nine-fused-ring compound with a doubly aza[5]helical geometry is by far the largest cationic polycyclic heteroaromatic with a central imidazolium core.