Base-Catalyzed Diels−Alder Reactions of 2H-Pyran-2,5-diones: A Mild Approach to Basiliolide B

A new class of base-catalyzed Diels−Alder reactions of 2H-pyran-2,5-diones has been developed using catalytic amount of dicyclohexylmethylamine in tert-butyl alcohol. This method has been successfully employed for construction of the tricyclic core of basiliolide B at room temperature with good yields and exclusive endo selectivity.