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.
Process for preparing 4'-trifluoromethyl-2-methylbiphenyl and 4'-trifluoromethyl-biphenyl-2-carboxylic acid from o-tolylmetallates
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, (2008/06/13)
The invention relates to a process for preparing a compound of the formula (I) in which R is methyl or carboxyl, which comprises coupling an ortho-tolylmetallate of the formula (II) with a compound of the formula (III) in which M is —MgF, —MgCl, —MgBr, —Mgl, —Li, —ZnF, —ZnCl, —ZnBr or —Znl and X is F, Cl, Br, I, N2+, straight-chain or branched (C1-C20)-alkoxy, arylsulfonate or alkylsulfonate in the presence of an Ni, Pd or platinum metal catalyst to give a compound of the formula (I) where R is CH3 and, if appropriate, oxidizing the compound of the formula (I) where R is CH3 to give the compound of the formula (I) where R is carboxyl.
