Isocoumarins a Privileged Scaffold: Isolation, Biosynthesis and Recent Progress in the Total Synthesis of Naturally Occurring Isocoumarins and Dihydroisocoumarins

Isocoumarins are naturally occurring benzo‐pyranones that constitute a class of polyketides derived from fungal metabolites and possess significant structural diversity and promising biological activity. Their core structural feature consists of a substituted benzene ring fused to a six‐membered lactone ring; in addition, extra substitution at the C 3 ‐position is also common. In this review, we primarily focus our attention on the total synthesis of few naturally occurring isocoumarins and dihydroisocoumarins. We will briefly discuss several methodological advances (substrate scope, sustainability advantages and limitations) for the isocoumarin and dihydroisocoumarin (DHIC) core construction. We have also delineated the chemistry and biology of several structural congeners of isocoumarins that have emerged in recent years.