167021-49-0Relevant articles and documents
In Situ Generation of ArCu from CuF2 Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient
Delpozo, Juan,Casares, Juan A.,Espinet, Pablo
supporting information, p. 4274 - 4284 (2016/03/16)
A bimetallic system of Pd/CuF2, catalytic in Pd and stoichiometric in Cu, is very efficient and selective for the coupling of fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p-cyanophenyl, p-nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by CuII, followed by disproportionation and transmetalation from the CuI(aryl) to PdII, upon which coupling takes place. CuIII formed during disproportionation is reduced to CuI(aryl) by excess aryl silane, so that the CuF2 system is fully converted into CuI(aryl) and used in the coupling. Moreover, no extra source of fluoride is needed. Interesting size selectivity towards coupling is found in competitive reactions of hindered aryl silanes. Easily accessible [PdCl2(IDM)(AsPh3)] (IDM = 1,3-dimethylimidazol-2-ylidene) is by far the best catalyst, and the isolated products are essentially free from As or Pd (2: In the Cu-promoted Hiyama process, CuF2 plays the role of two reagents to provide full conversion into the fluoride and copper is also required to transform bulky trialkoxysilanes in situ into CuAr. CuAr immediately transmetalates to Pd, which makes the otherwise inaccessible Pd-catalyzed coupling of bulky arylsilanes feasible and highly efficient.
Palladium catalyzed Suzuki C-C couplings in an ionic liquid: Nanoparticles responsible for the catalytic activity
Fernandez, Fernando,Cordero, Beatriz,Durand, Jerome,Muller, Guillermo,Malbosc, Franois,Kihn, Yolande,Teuma, Emmanuelle,Gomez, Montserrat
, p. 5572 - 5581 (2008/09/17)
A new family of functionalized ligands derived from norborn-5-ene-2,3- dicarboxylic anhydride has been used in Suzuki C-C cross-couplings between aryl boronic acids and aryl bromide derivatives in [BMI][PF6] (BMI = 1-n-butyl-3-methyl-imidazolium), using palladium acetate as catalytic precursor. High conversions and yields are obtained when amine ligands containing hydroxy groups are involved. TEM analyses after catalysis show the formation of small nanoparticles, in contrast to the agglomerates observed when nanoparticles are intentionally preformed, with a consequent decrease in the catalytic activity in the latter case. Some tests, including the correlation effect between solvent and ligand, are carried out to try to identify the true nature of the catalyst. All the results obtained suggest that formation of nanoparticles is required to lead to a catalytically active system. The Royal Society of Chemistry.
Production methods of alpha, alpha, alpha-trifluoromethylphenyl-substituted benzoic acid and intermediate therefor
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, (2008/06/13)
The present invention relates to a production method of compound [V] useful as an intermediate for medicaments and agrochemicals. The method includes reacting compound [III] with hexamethylenetetramine under heating to give compound [IV], and oxidizing the obtained compound [IV] with a halous acid salt or a ruthenium compound. According to the present invention, moreover, an organometallic compound having a tolyl group and compound [I] are cross-coupled in the presence of a catalyst to give compound [II] useful as an intermediate for medicaments and agrochemicals. The compound [II] is halogenated to give compound [III]. wherein X is halogen atom.