Pentakis(phenylethynyl)benzene and Hexakis(phenylethynyl)benzene: A Revision Concerning Two Far Too Similar Prototype Hydrocarbons

• Published in: European journal of organic chemistry Vol. 2004; no. 4; pp. 867 - 872
• Main Authors: Nierle, Jens, Barth, Dieter, Kuck, Dietmar
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.02.2004; WILEY‐VCH Verlag; Wiley
• Subjects: Alkynes; Chemistry; Chemistry, Organic; C−C coupling; Dehalogenation; Ethynylbenzenes; Palladium; Physical Sciences; Science & Technology; C-C coupling; BUILDING-BLOCKS; alkynes; ethynylbenzenes; COMPLEXES; ALPHA-AMINO-ACIDS; TRIBENZOTRIQUINACENES; SYMMETRY; PHENYLETHYNYLBENZENE DERIVATIVES; CHEMISTRY; palladium; SYSTEMS; LIQUID-CRYSTALLINE COMPOUNDS; dehalogenation; PERIPHERAL FUNCTIONALIZATION
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.200300644

A previously overlooked hydrodehalogenation reaction occurring during the multiple Pd0‐catalysed C−C coupling reaction between phenylacetylene and hexaiodo‐ and hexabromobenzene was found to give pentakis(phenylethynyl)benzene (“pentatolane”) as the major product, but no hexakis(phenylethynyl)benzene (“hexatolane”) under conditions previously claimed to yield the latter hydrocarbon. As an alternative to a viable route to hexatolane described in the literature, an independent synthesis of this hydrocarbon through sixfold Sonogashira coupling of hexakis(ethynyl)benzene with iodobenzene has been developed. Some physical and spectroscopic properties of hexatolane and of the hitherto unknown pentatolane have been determined after thorough purification by HPLC. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)