The Palladium Way to N-Heteroacenes

• Verfasst von: Bunz, Uwe H. F. [VerfasserIn]
• Verfasst von: Engelhart, Jens U. [VerfasserIn]
• Titel: The Palladium Way to N-Heteroacenes
• Verf.angabe: Uwe H. F. Bunz and Jens U. Engelhart
• E-Jahr: 2016
• Jahr: 17 February 2016
• Umfang: 10 S.
• Fussnoten: Gesehen am 25.05.2020
• Titel Quelle: Enthalten in: Chemistry - a European journal
• Ort Quelle: Weinheim : Wiley-VCH, 1995
• Jahr Quelle: 2016
• Band/Heft Quelle: 22(2016), 14, Seite 4680-4689
• ISSN Quelle: 1521-3765
• DOI: doi:10.1002/chem.201505018
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: acenes
• Sach-SW: electron transport materials
• Sach-SW: homogeneous catalysis
• Sach-SW: N-heterocycles
• Sach-SW: palladium
• K10plus-PPN: 1698736304

Abstract

Abstract Novel synthetic methodologies allow increasingly efficient access to known organic materials, as well as the preparation of otherwise inaccessible species. Pd-catalyzed coupling of aromatic dihalides to ortho-diaminoarenes furnishes embedded stable N,N?-dihydropyrazines expediently and in often excellent yields. The embedded N,N?-dihydropyrazines can then be oxidized by MnO2 to give substituted azatetracenes, azapentacenes, azahexacenes, and azaheptacenes, which are soluble, processable, and stable. This powerful Pd-catalyzed methodology allows the preparation of azaacenes, including diaza-, tetraaza- and hexaazaacenes. In combination with a suitable Pd precursor, Buchwald-type biarylphosphines have been shown to give excellent results. Activated dihalides such as 2,3-dihaloquinoxalines are coupled easily under simplified conditions, whereas 2,3-dibromoacenes require more stringent conditions and advanced catalyst precursors. Pd catalysts effect the assembly of azaacenes with otherwise difficult to obtain substitution patterns. High yields and flexibility make this method most attractive.