Stable Isobenzofurans

Significance

The synthesis of two stable, oxadisilole-fused isobenzofurans is reported. Trapping of the benzynes derived from benzobioxadi­silole and benzotrioxadisilole via fluoride-induced desilylation with furan gave the corresponding epoxynaphthalenes. Reaction of these compounds with 3,6-di-2-pyridyl-1,2,4,5-tetrazine afforded the desired isobenzofurans in good yields. The isobenzofurans proved reasonably stable at room temperature, surviving column chromatography over silica gel and providing sharp melting points. Various linear acenes were also synthesized by condensation of the isobenzofurans with DMAD and various benzyne derivatives followed by dehydration with LiAlH₄.