Azo Compounds as Key Intermediates in the Synthesis of Cinnolines. Recent Advances

Abstract

Over the past decades, azo compounds have emerged as versatile and efficient building blocks for the construction of cinnoline frameworks due to their ready availability, structural diversity, and unique reactivity profiles. This review provides a comprehensive overview of recent advances in the use of azo compounds for cinnoline synthesis, highlighting transition-metal-catalyzed C–H activation modern strategies, cycloaddition reactions and classical methods (von-Richter, Widman–Stoermer or Borsche–Herbert)