p-Sulfonic Acid Calix[n]arene Catalyzed Synthesis of Bioactive Heterocycles: A Review

Metal-free organocatalysts are becoming an important tool for the sustainable development of various bioactive heterocycles. On the other hand, during the last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review, we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse, biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, it is strongly believed that this review will surely attract those researchers who are interested in this fascinating organocatalyst.