On homogeneous gold/palladium catalytic systems

• Verfasst von: Hashmi, A. Stephen K. [VerfasserIn]
• Verfasst von: Lothschütz, Christian [VerfasserIn]
• Verfasst von: Döpp, René [VerfasserIn]
• Verfasst von: Ackermann, Martin [VerfasserIn]
• Verfasst von: De Buck Becker, Janosc [VerfasserIn]
• Verfasst von: Rudolph, Matthias [VerfasserIn]
• Verfasst von: Scholz, Christian [VerfasserIn]
• Verfasst von: Rominger, Frank [VerfasserIn]
• Titel: On homogeneous gold/palladium catalytic systems
• Verf.angabe: A. Stephen K. Hashmi, Christian Lothschütz, René Döpp, Martin Ackermann, Janosc De Buck Becker, Matthias Rudolph, Christian Scholz, and Frank Rominger
• Umfang: 15 S.
• Fussnoten: Gesehen am 06.09.2018
• Titel Quelle: Enthalten in: Advanced synthesis & catalysis
• Jahr Quelle: 2012
• Band/Heft Quelle: 354(2012), 1, S. 133-147
• ISSN Quelle: 1615-4169
• DOI: doi:10.1002/adsc.201000044
• Datenträger: Online-Ressource
• Sprache: eng
• Bibliogr. Hinweis: Erscheint auch als Druck-Ausgabe: On Homogeneous gold/palladium catalytic systems
• K10plus-PPN: 158075211X

Abstract

Two substrates containing an aryl iodide and an allenoate ester were prepared and the gold-induced cycloisomerisation to vinylgold(I) species and their proto-deauration as well as the intramolecular palladium-catalysed cross-coupling reactions were investigated. Switching to catalytic amounts of gold and palladium and stoichiometric amounts of silver did indeed furnish the product of a cycloisomerisation/intramolecular cross-coupling. Control experiments revealed that silver cannot substitute for gold or palladium in these reactions, but a different palladium catalyst in a different oxidation state also afforded the cycloisomerisation/intramolecular cross-coupling products in only slightly reduced yields. By ICP analysis the palladium was shown to contain gold only at the sub-ppm level. This shows how carefully results obtained with such systems have to be interpreted. Then a series of allylic and benzylic o-alkynylbenzoates were investigated in gold- and palladium-catalysed reactions. For esters of benzyl alcohol and cinnamyl alcohol no palladium co-catalyst was needed for the conversion. All reagents were thoroughly checked for palladium traces by ICP analysis in order to thoroughly exclude a gold/palladium co-catalysis. Optimisation of the gold complex, counter ion and solvent showed that gold(I) isonitrile pre-catalysts and silver triflate as activator in dioxane are suitable to convert a number of substrates with aryl, alkyl and even cyclopropyl substituents. Crossover experiments proved an intermolecular allyl transfer.