Recent Advances on Synthesis of 2H-Chromenes, and Chromenes Fused Hetrocyclic Compounds

Chromenes and 2H-Chromenes are vital components of natural products, pharmaceuticals, and agrochemicals that have captured the attention of researchers worldwide. These heterocyclic compounds represent an essential class of structural scaffolds, and the quest for their synthesis in a mild and straightforward way has gained significant momentum. Chromenes are oxygen-containing heterocycles that have been widely studied due to their potential medicinal properties. In the last two decades, researchers have made remarkable progress towards the synthesis of chromene based heterocyclic compounds using O-propargylated benzaldehydes as a substrate. These substrates are highly versatile and contain functional groups that make them ideal for a wide range of reactions. This review article provides an in-depth analysis of the latest advances in alkynes' functionalization, emphasizing the substrate scope, limitations, regioselectivity control, and applications of these reactions. The review also covers a range of critical methods and strategies, including multicomponent reactions, used for the general synthesis of numerous types of chromene derivatives.