Synthesis of pi-conjugated systems bearing thiophene and pyrrole heterocycles through palladium catalyzed cross-coupling reactions.

摘要

A series of thienylpyrroles and bithienylpyrroles together with their formyl derivatives 5aed weresynthesized using commercially or readily available coupling components, through three different palladium catalyzed cross-coupling reactions (Suzuki-Miyaura, Stille and decarboxylative coupling). Thesynthesis of compounds 5 via the Suzuki-Miyaura reaction produced the title compounds in better yieldsthan the other coupling reactions, while, decarboxylative coupling resulted in the lower yields.UV-visible and 1H NMR studies confirm the existence of significant intramolecular charge transfer (ICT)from the donor pyrrole heterocycle to the acceptor group and a high polarizability of the wholepi-conjugated systems. Together these characteristics indicate their strong potential as versatile precursors for the preparation of push-pull heterocyclic compounds for optical applications.