An overview of recent advances in the catalytic synthesis of substituted pyrans

Substituted pyrans (4H-Chromenes) are the most significant structural scaffolds in synthetic and medicinal chemistry. They are found in an array of natural products, medicines, and phytochemical compounds, bearing an explicit of pharmacological activities. The structural importance of substituted pyrans has elicited a huge upsurge in the field of synthesis and biology. Different synthetic approaches of 4H-chromene scaffolds have been discussed systematically to emphasize their significance in the scientific world. The present article summarizes the different synthetic strategies of substituted pyran derivatives via acid-base catalysis, ionic liquids, nanomaterials, deep eutectic solvents, bio-based, visible light, metal catalyzed, and so forth developed in the last decade. Moreover, this article will definitely contribute to the scientific world for developing synthetically and biologically important pyran analogs.