Selenophene, a Twin-Brother of Thiophene?

Abstract

Differences in chemistry and NMR-properties between selenophene and thiophene will be discussed. Methods for the preparation of selenophenes, especially the preparation of selenophene through the reaction between acetylene and selenium, will be treated. Atropisomerism in 3,3'-biselenienyls and 3,3'-bithienyls will be discussed. Substituent effects on the 77Se shifts in selenophenes will be analysed. The ring-opening of 3-selenienyllithium derivatives will be compared with that of the corresponding 3-thienyllithium derivatives. Emphasis will be put on tautomerism and reactions of the 2- and 3-hydroxy-systems, reflecting the differences in the aromaticities of thiophene and selenophene. The preparation and reactions of the four classical isomeric selenoloselenophenes, the non-classical selenoloselenophene system, as well as selenolothiophenes will be treated. The preparation of other condensed selenophenes will be touched upon. Other topics, which will be discussed, is the preparation of β-2- and β-3-selenienylalanines. the reactivity of the heteroatom as well as organic metals derived from selenophenes.