Palladium-catalyzed coupling reactions in flavonoids: A retrospective of recent synthetic approaches

Abstract

Palladium-catalyzed coupling reactions are among the most important for forming carbon–carbon bonds in organic synthesis. These reactions are frequently employed in the synthesis of heterocycles, natural products, and other biologically active molecules. Flavonoids, a notable group of natural products, have versatile structures and diverse biological activities. They can be divided into subclasses, including flavones, flavonols, chalcones, isoflavones, flavanones, etc. The search for the total synthesis of these natural products, as well as derivatives with improved biological activities, has been driving the use of coupling reactions as a key strategy for joining two large portions of those structures in a single step. This review summarizes the synthetic methodologies that have been used during the last decade involving palladium-catalyzed coupling reactions with several subclasses of flavonoids.