Synthesis of Highly Functionalized Bis(4<i>H</i>-chromene) and 4<i>H</i>-Benzo[<i>g</i>]chromene Derivatives via an Isocyanide-Based Pseudo-Five-Component Reaction

Abstract

The reactive intermediates generated by the addition of alkyl, aryl, and alicyclic isocyanides to dialkyl acetylenedicarboxylates were trapped by 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione or 2-hydroxynaphthalene-1,4-dione to produce highly functionalized bis(4H-chromene)- and 4H-benzo[g]chromene-3,4-dicarboxylate derivatives in fairly good yields in CH(3)CN at room temperature. These compounds are closely related to the ring systems pentalongin, dehydroherbarin, 1,3-disubstituted-3,4-dehydropyranonaphthoquinones, and 3-arylpyranonaphthoquinones, which have a broad spectrum of biological activity.