Coumarin-Fused Nitrogenous Heterocycles: An Exploration of Annulation Strategies

Driven by advances in the pharmaceutical industry and in materials science, the search for innovative strategies for the synthesis and functionalization of coumarin-fused nitrogenous heterocycles has intensified. These compounds, which combine the bioactive coumarin core with various nitrogen-containing heterocycles, are of significant interest due to their diverse biological activities and promising potential applications. Traditional methods for synthesizing these hybrid structures often encounter challenges such as low yields, limited functional group compatibility and rigorous reaction conditions. To address these challenges, there is a growing need for the development of advanced synthetic strategies that can effectively and efficaciously produce the aforementioned heterocyclic scaffolds. Towards this goal, annulation strategies (e.g., cyclization, condensation, multicomponent reactions, transition-metal-catalyzed reactions, etc.) represent pivotal techniques to construct coumarin-fused nitrogenous heterocycles, which evade the constraints of conventional approaches. In this account, we highlight our recent progress on the construction of these complex heterocyclic scaffolds in order to pave the way for further developments in this dynamic field.

1 Introduction

2 Exploring Acid-Catalyzed Annulation Strategies

3 Annulation Strategies Based on C–H Activation

4 Oxidative Annulation Strategies

5 Conclusion