Diels-Alder Reactions of [1]Benzothieno[3,2-b]furan

Abstract

[1]Benzothieno[3,2-b]furan reacts with substituted dienes 2 as a dienophile under formation of substituted tetrahydro[1]benzothieno[3,2-b][1]benzofuran derivatives 3-14. The cycloaddition is endo-stereoselective. Aromatization of the products leads to a series of new fused [1]benzothieno[3,2-b][1]benzofurans 17-24. The 1H NMR spectra of the new compounds were fully assigned.