ChemInform Abstract: Palladium—Poly(3‐aminoquinoline) Hollow‐Sphere Composite: Application in Sonogashira Coupling Reactions (original) (raw)
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Catalytic Sonogashira couplings mediated by an amido pincer complex of palladium
Inorganic Chemistry Frontiers, 2014
This work describes the efficacy of [PNP]PdCl (1a), where [PNP] − = bis(2-diphenylphosphinophenyl) amide, as a catalyst precursor for C sp-C sp2 bond-forming cross-coupling reactions of terminal alkynes with aryl halides in the presence of copper bromide and aliphatic amines in ethereal solutions under mild conditions. This catalysis is compatible with acetylenes that are alkyl, alkenyl, (hetero)aryl, or silyl substituted and aryl iodides or bromides that are electronically activated, neutral, or deactivated. The low reaction constants of 0.82(6) and 0.97(7) obtained from Hammett plots of competitive reactions employing electronically distinct aryl iodides and terminal alkynes, respectively, are likely suggestive of irrelevance of the rate-determining step in these catalytic transformations to oxidative addition of aryl halides or generation of mono-substituted acetylides. In sharp contrast, reactions employing a phosphorus-bound isopropyl derived 1b gave rather unsatisfactory results, highlighting a profound phosphorus substituent effect on this aryl alkynylation catalysis. † Electronic supplementary information (ESI) available: X-ray crystallographic data for 1b, a catalytic reaction profile, details of competition reactions to construct Hammett plots, and NMR spectra of products isolated. CCDC 956287.
Chemical Papers, 2014
A new palladium-bidentate complex [m-C6H4(CH2ImMe)2(PdCl2)] (III) was prepared in two steps. In the first step, [m-C6H4(CH2ImMeAgCl)2] (II) (Im = imidazole moiety) was obtained by reacting imidazolium salt [m-C6H4(CH2ImMe)2]Cl2 (I) (prepared by quaternisation of Nmethylimidazole with 1,3-bis(chloromethyl)benzene) and Ag2O in CH2Cl2. In the next step, treatment of (II) with Pd(CH3CN)2Cl2 afforded complex III which was evaluated for its catalytic activity for C-C bond-formation reactions by examining the coupling reaction of 3-iodoanisole with phenylacetylene in the Sonogashira reaction. In addition, 3-methoxybiphenyls were obtained with good to excellent yields by Suzuki coupling reactions of 3-iodoanisole with phenylboronic acids or phenylborates salts in the presence of this complex.
Tetrahedron Letters, 2010
A new polystyrene anchored Pd(II) azo complex has been synthesized and characterized. The present Pd(II) azo complex behaves as a very efficient heterogeneous catalyst in the Suzuki coupling and Sonogashira coupling reaction in water medium. Aryl halides, coupled with phenylboronic acids (Suzuki-Miyaura reaction) or terminal alkyne (Sonogashira reaction), smoothly afford the corresponding crosscoupling products in excellent yields (83-100% yield for Suzuki reaction and 68-96% yield for Sonogashira reaction of aryl halides) under phosphine-free reaction conditions in the presence of polystyrene anchored Pd(II) azo complex catalyst in water medium. Furthermore, the catalyst has shown good thermal stability and recyclability. This polymer-supported Pd(II) catalyst could be easily recovered by simple filtration of the reaction mixture and reused for more than six consecutive trials without a significant loss of its catalytic activity.
Journal of the Iranian Chemical Society, 2020
Reforming mesoporous silica was provided by the reaction of SBA-15 with (3-aminopropyl)triethoxysilane, the product of which was treated with furfural to give SBA-propyl-imine-furan. In the next step, palladium chloride was attached to the functionalized SBA-15, so Pd nanoparticles immobilized on the mentioned catalyst for providing an applicable catalyst to use in the Sonogashira cross-coupling reaction. The high stability and performance of functionalized heterogeneous hybrid