Synthesis of 4-Aryldihydrocoumarins via a Sequential Michael Addition–Lactonization Route

Background: Coumarin and its derivatives have attracted the attention of synthetic chemists due to their importance in pharmaceutical and medicinal chemistry. The acid-catalyzed cyclization route constitutes the method of choice to access these important compounds. Objective: In this paper, we have discussed the synthesis of 4-aryldihydrocoumarins via a one-pot p-sulfonic acid calix[4]arene catalyzed reaction. Method: The easily prepared calix[4]arene derivative catalyzes a sequential reaction involving Michael addition followed by intramolecular lactonization to afford the title compound in decent yield. Results: The described methodology is devoid of any metal salt, thus making it a very appealing protocol to safely produce dihydrocoumarins of pharmacological importance. Conclusion: The easy recovery, non-toxicity, and reusability of the catalytic system are some of the other advantages of our procedure. In addition, the catalyst efficiency is not compromised after its successive use in reactions.