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

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• 作者：M. Cidá ; lia R. Castro ; M. Manuela M. Raposo ; ^{mfox@quimica.uminho.pt" class="auth_mail" title="E-mail the corresponding author}
• 关键词：π-Conjugated systems ; Formyl-substituted (bi)thienylpyrroles ; Thiophene ; Pyrrole ; Suzuki-Miyaura coupling ; Stille coupling ; Decarboxylative coupling ; UV&ndash ; vis spectroscopy ; Nonlinear optical (NLO) precursors
• 刊名：Tetrahedron
• 出版年：2016
• 出版时间：14 April 2016
• 年：2016
• 卷：72
• 期：15
• 页码：1881-1887
• 全文大小：582 K

文摘

A series of thienylpyrroles and bithienylpyrroles together with their formyl derivatives ng class="boldFont">5ang>–ng class="boldFont">dng> were synthesized using commercially or readily available coupling components, through three different palladium catalyzed cross-coupling reactions (Suzuki-Miyaura, Stille and decarboxylative coupling). The synthesis of compounds ng class="boldFont">5ng> via the Suzuki-Miyaura reaction produced the title compounds in better yields than 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 whole π-conjugated systems. Together these characteristics indicate their strong potential as versatile precursors for the preparation of push-pull heterocyclic compounds for optical applications.