Synthetic strategies toward 3-arylcoumarins: From classical condensation to sustainable C–H arylation

3-Arylcoumarins are important coumarin derivatives with diverse applications in medicinal chemistry, materials science, and chemical biology. However, efficient and selective construction of the C3–aryl bond remains a significant synthetic challenge. This review provides a focused and critical analysis of methodologies for synthesizing 3-arylcoumarins, including classical condensation, transition-metal-catalyzed cross-coupling and annulation, radical-mediated, visible-light photoredox, mechanochemical, and emerging sustainable approaches. Rather than presenting a chronological compilation, the reported methods are compared in terms of reaction mechanisms, catalyst systems, substrate scope, functional-group tolerance, efficiency, selectivity, recyclability, scalability, and green chemistry aspects. Recent advances are evaluated alongside established strategies, highlighting the shift toward atom-economical, metal-free, recyclable, and energy-efficient processes. The review further identifies key limitations and challenges while highlighting future opportunities in photoredox and electrochemical synthesis, heterogeneous catalysis, mechanochemistry, and continuous-flow technologies. Overall, it provides a practical framework for selecting efficient and sustainable routes to structurally diverse 3-arylcoumarins.