Recent Advances on Asymmetric Synthesis of Benzofused Six-Membered Oxygen-Containing Heterocycles (2020–2025)

Abstract Asymmetric synthesis due to distinct physiological effects of enantiomers has been a key focus in both academic and industrial laboratories for decades, offering challenges for chemists and enabling the development of valuable pharmaceuticals and agrochemicals. Medium-ring heterocycles, particularly benzofused oxygen-containing six-membered rings such as pyrones and pyrans, represent crucial structural motifs in synthetic and natural products and drug discovery. These scaffolds exhibit significant pharmacological activities and find additional applications in materials science, as well as in the agricultural and food industries. This review summarizes the recent advances over the past 5 years (2020–2025) in the asymmetric synthesis of valuable scaffolds such as isocoumarins, coumarins, flavonoids/chromones, and chromanes, encompassing both transition-metal-catalyzed approaches and metal-free organocatalytic strategies. It highlights the principal reaction types, strategies for stereocontrol, reported yields, and applications in synthesis of natural products.