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RESEARCH PRODUCT
The first catalytic method for Heck alkynylation of unactivated aryl bromides (copper-free Sonogashira) in an ionic liquid: 1 mol-percent palladium/triphenylphosphane/pyrrolidine in [BMIM][BF4] as a simple, inexpensive and recyclable system
Julien BoudonPhilippe MeunierJean-cyrille HiersoMichel Picquetsubject
copper-free SonogashiraIonic bondingchemistry.chemical_elementSonogashira coupling010402 general chemistry01 natural sciences7. Clean energyHeck alkynylationPyrrolidineCatalysischemistry.chemical_compound[ CHIM.CATA ] Chemical Sciences/CatalysisHeck reactiontriphenylphosphaneOrganic chemistryPhysical and Theoretical ChemistryAlkylComputingMilieux_MISCELLANEOUSionic liquidchemistry.chemical_classificationcatalysis010405 organic chemistryArylOrganic ChemistryGeneral Medicine[CHIM.CATA]Chemical Sciences/CatalysispalladiumCombinatorial chemistrymethylimidazolium0104 chemical sciencesSolventchemistryIonic liquidPalladiumdescription
Herein we report the studies of Heck alkynylation (copper-free Sonogashira) with aryl halides (I, Br, Cl) employing various metallic precursors, tertiary phosphanes and bases in [BMIM][BF4] as the solvent. As a result, we provide the first method that allows the coupling of a large array of substrates, either activated or deactivated bromides in an ionic liquid. Furthermore, the system of highest efficiency is unexpectedly the simplest and cheaper combination that employs [Pd(η3-C3H5)Cl]2/PPh3 at only a 1 mol-% loading with pyrrolidine as the base and in the absence of a copper salt. The coupling of sterically and electronically deactivated bromides bearing different functional groups to aryl- and alkyl acetylenes, as well as the possibility of recycling, make these results of high interest to the future development of Heck- and Sonogashira-type reactions in ionic liquids.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
year | journal | country | edition | language |
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2007-01-01 |