- The expedient and regioselective metalation of unprotected biphenyl-2-, -3-, and -4-carboxylic acids
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Unprotected biphenyl-2-carboxylic acid can be cleanly metalated with sec-butyllithium at the position adjacent to the carboxylate and can then be subjected to site-selective electrophilic substitution. The remote C2′-position is attacked by the superbasic
- Tilly, David,Samanta, Subhendu S.,Castanet, Anne-Sophie,De, Asish,Mortier, Jacques
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- Mechanochemical Solvent-Free Suzuki–Miyaura Cross-Coupling of Amides via Highly Chemoselective N?C Cleavage
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Although cross-coupling reactions of amides by selective N?C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challe
- Ma, Yangmin,Shao, Lei,Szostak, Michal,Wang, Ruihong,Zhang, Jin,Zhang, Pei
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supporting information
(2022/01/04)
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- Green and sustainable palladium nanomagnetic catalyst stabilized by glucosamine-functionalized Fe3O4@SiO2 nanoparticles for Suzuki and Heck reactions
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A novel magnetic and heterogeneous palladium-based catalyst stabilized by glucosamine-functionalized magnetic Fe3O4@SiO2 nanoparticle was synthesized. The strategy relies on the covalently bonding of glucosamine to cyanuric chloride-functionalized magnetic nanoparticles followed by complexation with palladium. The structure of magnetic nanocatalyst was fully determined by FT-IR, XRD, DLS, FE-SEM, TEM, ICP, UV-Vis, TGA, VSM, and EDX. The obtained results confirmed that the palladium nanoparticles stabilized by glucosamine immobilized onto the magnetic support exhibited high activity in cross-coupling reactions of Suzuki-Miyaura and Mizoroki-Heck. Various aryl halides were coupled with arylboronic acid (Suzuki cross-coupling reaction) and olefins (Heck reactions) under the green conditions to provide corresponding products in high to excellent yields. Interestingly, the catalyst can be easily isolated from the reaction media by magnetic decantation and can subsequently be applied for consecutive reaction cycles (at least seven times) with no notable reduction in the catalytic activity.
- Eslahi, Hassan,Sardarian, Ali Reza,Esmaeilpour, Mohsen
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- Sustainable and recyclable magnetic nanocatalyst of 1,10-phenanthroline Pd(0) complex in green synthesis of biaryls and tetrazoles using arylboronic acids as versatile substrates
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A magnetic nanocatalyst was purveyed as a heterogeneous recoverable palladium-based catalyst anchored on green, sustainable and phosphine free support. Resulted Fe3O4@SiO2-Phen-Pd(0) nanocatalyst bearing powerful phenanthroline ligand was thoroughly characterized by physicochemical approaches like UV–vis, FT-IR, EDX, XRD, TGA, ICP, VSM, DLS, FESEM, and TEM analyses. After finding trustable data, the obtained magnetic catalyst was considered to be applied in the Suzuki-Miyaura type C-C couplings and getting corresponding tetrazoles using arylboronic acid derivatives as alternate precursors of aromatic halides and stupendous data were observed.
- Bagherzadeh, Nastaran,Sardarian, Ali Reza,Eslahi, Hassan
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- Palladium(II) catalyzed Suzuki C–C coupling reactions with imino- and amino-phosphine ligands
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A new series of bidentate PN type imino- (1–3) and amino-phosphine ligands (4–6) and their palladium(II) complexes [Pd(PN)Cl2] (1a–6a) have been synthesized and fully characterized using spectroscopic and analytical methods, including 31P, 1H, 13C NMR and FTIR spectroscopy and high resolution mass spectroscopy. The catalytic activities of the Pd(II) complexes were investigated for the Suzuki C–C coupling reactions of phenylboronic acid with aryl bromides using a substrate to catalyst ratio of 500/1. The effect of base, temperature and solvent has been investigated, and the highest reaction rates were observed at 80 °C in dimethylformamide (DMF) with K2CO3 as the base in 12 h. Under optimized reaction conditions, generally higher coupled product was obtained with substituted aryl bromides, including both electron-withdrawing (-formyl and -aceto) or -donating groups (-methyl and -methoxy) at -ortho or -para positions, except 2-bromoacetophenone which has bulkier -aceto group compared to the other aryl bromides.
- Kemal Y?lmaz, Mustafa,?nce, Simay,Y?lmaz, Sevilay,Kele?, Mustafa
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p. 252 - 258
(2018/06/26)
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- Efficient scavenging of Ph3P and Ph3P=O with high-loading merrifield resin
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(formula presented) A simple, highly effective method for removing triphenylphosphine and/or triphenylphosphine oxide from reaction mixures is described. Commercially available high-loading chloromethylated polystyrene 1, modified in situ with Nal, acts as a scavenger resin. Several coupling reactions catalyzed by Pd(0) or Ni(0) which require the removal of triphenylphosphine are tested.
- Lipshutz, Bruce H.,Blomgren, Peter A.
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p. 1869 - 1871
(2007/10/03)
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- Palladium-catalyzed cross-coupling reactions of arenediazonium tetrafluoroborates with aryl- And alkeriylboronic acids
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Arcnediazonium tetrafluoroborates undergo a facile and efficient palladium-catalyzed cross-coupling reaction with aryl- and alkenylboronic acids at ambient temperature, without addition of base. The reaction described is characterized by a high chemoselectivity because bromide and trifiate functional groups are tolerated. Eisevier,.
- Darses, Sylvain,Jeffery, Tuyet,Jean-Louis,Demoute, Jean-Pierre,Genet, Jean-Pierre
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p. 1095 - 1102
(2007/10/03)
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- Cross-coupling of arenediazonium tetrafluoroborates with arylboronic acids catalysed by palladium
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Suzuki cross-coupling of various arenediazonium tetrafluoroborates and arylboronic acids is described for the first time in the presence of a catalytic amount of Pd(OAc)2, at ambient temperature and in the absence of both base and phosphine ligand.
- Darses, Sylvain,Jeffery, Tuyet,Genet, Jean-Pierre,Brayer, Jean-Louis,Demoute, Jean-Pierre
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p. 3857 - 3860
(2007/10/03)
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- Aroyl Peroxides. Part 7. The Effects of Additives on the Thermolysis of Aroyl Peroxides in Arenes and the Elimination of Possible Complications in the Measurement of Partial Rate Factors for Phenylation
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Competitive homolytic arylation of arenes has been carried out under conditions in which biaryl formation is maximised.Improved yields of biaryl were obtained with o-chloroanil, nitro- and nitroso-compounds, and transition metal salts; nitrosobenzene, pentafluoronitrosobenzene, copper(II)benzoate, and iron(III)benzoate caused nearly theoretical yields of biaryl and aroic acid.Partial rate factors, measured under such conditions, are free from uncertainties arising from the selective removal of ?-complexes by side-processes such as dimerisation.The possibility that arenes form complexes with aryl radicals or their precursors as a necessary part of the selection process between substrate molecules was not confirmed in studies of the application of the additivity principle and of the multiplication rule, and of variation in the relative concentration of the two competing arenes.The absence of any discrepancies indicates that the measured partial rate factors are not influenced by such putative complex formation.The mechanism of action of these catalysts has been investigated.
- Bolton, Roger,Dailly, Bryce N.,Hirakubo, Kazuko,Lee, Kong Hung,Williams, Gareth H.
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p. 1109 - 1120
(2007/10/02)
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