One-Pot Synthesis of Biscoumarin and Dihydropyrano[c]chromene Derivatives in the Presence of Organocatalysts under Solvent-Free Conditions

A simple and efficient synthesis of biscoumarin and dihydropyrano[c]chromene derivatives using catalytic amounts of imidazole or isoquinoline as organocatalyst under solvent-free conditions is reported. The present procedure offers advantages such as high to excellent yields, short reaction times, inexpensive operation, solvent-free conditions, reduced environmental consequences and simple workup.