A Pronounced Anionic Effect in the Pd-Catalyzed Buchwald–Hartwig Amination Reaction Revealed in Phosphonium Salt Ionic Liquids

✍ Scribed by James McNulty; Sreedhar Cheekoori; Timothy P. Bender; Jennifer A. Coggan

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 107 KB
• Volume: 2007
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200700005

✦ Synopsis

Abstract

The Pd‐mediated Buchwald–Hartwig amination reaction of aryl halides in a phosphonium salt ionic liquid consisting of a trihexyl(tetradecyl)phosphonium cation with a range of anions has been investigated. A pronounced anionic effect was uncovered with the reaction proceeding readily with weakly nucleophilic diarylamines only in the presence of noncoordinating anions. A mechanism is postulated to explain these results and it involves a rate‐limiting ligand exchange step that proceeds through a dissociative pathway.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)