Synthesis, Structures, and Reactivities of Bithiophene Derivatives Bridged with Bis(spirodienone) Unit

Abstract

Bithiophene derivatives bridged with a bis(spirodienone) unit were synthesized and characterized. Lithiation of the thiophene rings of an unsubstituted derivative proceeded without decomposition of the bis(spirodienone) skeleton. Palladium-catalyzed cross-coupling reactions (Suzuki-Miyaura, Sonogashira) with bromides afforded a variety of pai-extended derivatives. Bond breaking and formation under redox conditions were observed by cyclic voltammetry. Conformational change between the s-cis and s-trans forms of bithiophene under redox conditions will be a key feature of control of the structures and properties of the compounds.