Un Nouveau type d'ouverture de sélénophénes condensés

A condensed selenophene ring can be opened by selenium-metal interconversion, when the selenium atom is α to a five-membered aromatic ring, as in selenopheno 2,3-b] thiophene. In tricyclic compounds bearing 2,3-b] condensed triophene and selenophene rings, the selenophene ring open, whether in central or in lateral positions. When the tricyclic compound bears two 2,3-b] condensed selenophene rings, only the central selenophene ring opens by interconversion. Corresponding 3,2-b]isomers do not undergo this ring opening.