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A Pronounced Anionic Effect in the Pd‐Catalyzed Buchwald–Hartwig Amination Reaction Revealed in Phosphonium Salt Ionic Liquids
Author(s) -
McNulty James,
Cheekoori Sreedhar,
Bender Timothy P.,
Coggan Jennifer A.
Publication year - 2007
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700005
Subject(s) - chemistry , phosphonium , phosphonium salt , amination , ionic liquid , halide , medicinal chemistry , nucleophile , aryl , catalysis , salt (chemistry) , ligand (biochemistry) , organic chemistry , polymer chemistry , inorganic chemistry , biochemistry , alkyl , receptor
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)