Copper-catalyzed N-arylation of pyrroles: an overview

N-Arylated pyrroles have a wide range of applications in pharmaceuticals, the agrochemical industry and organic synthesis. They are intermediates for the formation of many biologically active compounds and natural products. Over the past decades, numerous protocols have been established for the efficient synthesis of N-aryl pyrroles, amongst which reactions using transition metal-based catalyst/mono- or bidentate ligand systems play an important role as they involve milder reaction conditions, affording excellent yields of the products. Amid these methods, the lion's share lies in copper catalysis. Many copper-based compounds are efficient as catalysts for organic synthesis, they are economical and nearly non-toxic. In this review, we focus on the copper-catalyzed C-N cross-coupling reactions of various aryl electrophiles with a range of nucleophilic pyrroles under various reaction conditions, covering the literature up to 2021.