Recent advances in the tandem copper-catalyzed Ullmann–Goldberg N-arylation–cyclization strategies

Abstract

N–Aryl bond formation under copper catalysis has played a pivotal role and has been extensively used as a key step in the total syntheses of several therapeutic molecules. The construction of fused N-heterocycles remains a flourishing area of research because of their potential importance in drug discovery research and functional materials. On the other hand, tandem reactions provide facile ways to access complex organic molecules by reducing the synthetic steps. This review article provides a detailed overview of the tandem reactions developed in the past two decades, comprising N-arylation–cyclization strategies, including mechanistic aspects, driven by copper catalysts to furnish biologically significant fused N-heterocyclic moieties. The protocols described enlighten the prominence of the copper-catalyzed N-arylation–cyclization tandem strategies; exploration in this direction may open new avenues, inspire the design of new and creative tandem reaction strategies, and may unveil novel transformations with unprecedented reaction mechanisms.