Annelated furans. IV. Diels-Alder synthesis of dibenzofurans

Abstract

The Diels-Alder reaction of 2-vinylbenzofurans with acetylenic dienophiles has been shown to provide a valuable synthetic route to polyfunctional dibenzofurans. Ethylenic dienophiles also react readily with 2-vinylbenzofurans and provide access to 1,2,3,11-tetrahydrodibenzofurans. The structure of the euparin-maleic anhydride adduct has been established.