Abstractmagnified imageA mild, efficient method utilizing a copper‐diamine catalyst at room temperature is reported for the coupling of hindered imidazoles with unsubstituted, ortho‐substituted, and bis‐ortho‐substituted boronic acids in good to excellent yields. Aryl halides do not reaction under these conditions permitting sequential N‐arylation reactions.
It was determined that diaryliodonium(III) triflates bearing a trimethoxybenzene (TMP) auxiliary are more reactive than the reported selective aryl-transfer iodonium salts in the N-arylation of benzimidazoles and other types of azole compounds under catalytic conditions. The TMP-iodonium(III) salts can thus effectively facilitate the reaction at 50 °C or below, producing the corresponding N-arylated