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.

The reactivity of alicyclic ketazines in criss-cross cycloadditions was investigated. They react with potassium cyanate and ammonium thiocyanate in the presence of acetic acid to form spirocyclic perhydro[1,2,4]triazolo[1,2-alpha][1,2,4]triazole-1,5-diones and perhydro[1,2,4]triazolo[1,2-alpha][1,2,4]triazole-1,5-dithiones, respectively, in relatively high yields.

6,7-Bis(alkyloxy)-2,3-dihydrophthalazine-1,4-diones self-assemble into lactim-lactam trimeric disks in solution as demonstrated by SEC and NMR. With suitable substituents, as in Phthal8, Phthal12, and Phthal16, these disks self-organize into a thermotropic, columnar, discotic phase. The disubstituted phthalhydrazide unit thus represents a general motif for the recognition-induced generation of ...

Readily prepared 2-alkyl-2-azidopropylcycloalkyl-1,3-diones undergo intramolecular Schmidt rearrangement with a range of hard Lewis acids, leading to indolizidinediones and pyrroloazepinediones. Chiral aluminium-based Lewis acids could also be used to mediate this symmetry-breaking transformation, but no significant asymmetric induction was observed.