Diverse synthesis of pyrano[3,2-c]coumarins: A brief update

Functionalized pyranocoumarins are an important class of oxygen-containing heterocyclic compounds. Fused coumarin systems, in particular pyranocoumarins, are abundant in nature and constitute building blocks for many natural products found across the plant kingdom. Pyranocoumarin derivatives have been found to possess antifungal, insecticidal, anticancer, anti-HIV, anti-inflammatory, antioxidant, and antibacterial activities. Synthesis of this moiety from the easily available chemicals is desirable due to its tremendous use in the various branches of chemistry. Owing to the broad spectrum of biological properties and natural occurrence, pyrano[3,2-c]coumarins have become attractive synthetic targets from medicinal chemistry point of view. This short review discusses on the synthesis of this scaffold employing different strategies including mechanistic illustrations.