- Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
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Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
- Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
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supporting information
(2020/09/18)
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- Orthogonal Nanoparticle Catalysis with Organogermanes
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Although nanoparticles are widely used as catalysts, little is known about their potential ability to trigger privileged transformations as compared to homogeneous molecular or bulk heterogeneous catalysts. We herein demonstrate (and rationalize) that nanoparticles display orthogonal reactivity to molecular catalysts in the cross-coupling of aryl halides with aryl germanes. While the aryl germanes are unreactive in LnPd0/LnPdII catalysis and allow selective functionalization of established coupling partners in their presence, they display superior reactivity under Pd nanoparticle conditions, outcompeting established coupling partners (such as ArBPin and ArBMIDA) and allowing air-tolerant, base-free, and orthogonal access to valuable and challenging biaryl motifs. As opposed to the notoriously unstable polyfluoroaryl- and 2-pyridylboronic acids, the corresponding germanes are highly stable and readily coupled. Our mechanistic and computational studies provide unambiguous support of nanoparticle catalysis and suggest that owing to the electron richness of aryl germanes, they preferentially react by electrophilic aromatic substitution, and in turn are preferentially activated by the more electrophilic nanoparticles.
- Fricke, Christoph,Sherborne, Grant J.,Funes-Ardoiz, Ignacio,Senol, Erdem,Guven, Sinem,Schoenebeck, Franziska
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p. 17788 - 17795
(2019/11/13)
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- Visible-Light-Promoted, Catalyst-Free Gomberg-Bachmann Reaction: Synthesis of Biaryls
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Biaryls were synthesized via a novel visible-light-promoted Gomberg-Bachmann reaction that does not require a photosensitizer or any metal reagents. The formation of an electron donor-acceptor complex between aryl diazonium salts and pyridine allows, under visible-light irradiation, the synthesis of biaryls in moderate-to-high yields.
- Lee, Juyoung,Hong, Boseok,Lee, Anna
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p. 9297 - 9306
(2019/08/12)
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- Selective Suzuki-Miyaura monocouplings with symmetrical dibromoarenes and aryl ditriflates for the one-pot synthesis of unsymmetrical triaryls
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The various parameters that would permit selective Suzuki-Miyaura monocouplings of symmetrical dihaloarenes were studied. High selectivity and efficiency can be obtained for a broad range of substrates by using operationally simple conditions and widely available reagents. The 38 different examples described provide a valuable toolbox for the rapid access to unsymmetrical triaryls, as illustrated by the preparation of diarylpyridine 8, terphenyl 9, and diarylpyrrole 10. By studying several key parameters, the factors that allow selective Suzuki-Miyaura monocoupling of symmetrical dihaloarenes have been outlined. This study serves as the basis for the efficient synthesis of unsymmetrical triaryls from symmetrical dibromoarenes and aryl ditriflates by a one-pot desymmetrizing double Suzuki-Miyaura coupling. Copyright
- Minard, Corinne,Palacio, Carole,Cariou, Kevin,Dodd, Robert H.
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p. 2942 - 2955
(2014/05/20)
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- Monoarylation of dibromoarenes by simple palladium catalyst systems: Efficient synthesis of bromobiaryls from dibromoarenes and arylboronic acids
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The Pd/C/Ph3P- and Pd(PPh3)4/Ph 3P-catalyzed cross-couplings of dibromoarenes with arylboronic acids to form bromobiaryls in good to excellent yields are described. Our study showed that readily available Pd/C/P
- Dong, Cheng-Guo,Liu, Tao-Ping,Hu, Qiao-Sheng
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scheme or table
p. 1081 - 1086
(2009/09/30)
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- Solid-phase synthesis with resin-bound triarylbismuthanes: Traceless and multidirectional cleavage of unsymmetrical biphenyls
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A multistep solid-phase organic synthesis with resin-bound bismuth linker is described. The flexibilities inherent in this system through novel chemoselective cross-coupling reactions, in conjunction with multidirectional and/or traceless cleavage methodologies, are exploited.
- Rasmussen, L. Kyhn,Begtrup, Mikael,Ruhland, Thomas
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p. 1230 - 1232
(2007/10/03)
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- Controlled monoarylation of dibromoarenes in water with a polymeric palladium catalyst
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A highly selective monoarylation of dibromoarenes was performed via the Suzuki-Miyaura cross-coupling with arylboronic acids with an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported phosphine-palladium complex in water under heteroge
- Uozumi, Yasuhiro,Kikuchi, Makoto
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p. 1775 - 1778
(2007/10/03)
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