Diazonium salts as substrates in palladium-catalyzed cross-coupling reactions.
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Biomedical subjects
Marcial Moreno-Mañas
Publications and source records attributed to Marcial Moreno-Mañas.
Structural analysis of chiral complexes of palladium(0) with 15-membered triolefinic macrocyclic ligands.
The complete structural analysis of the palladium complexes of the triolefinic macrocycles (E,E,E)-1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-trienes, which featured from three identical to three different aryl groups, was achieved by performing X-ray diffraction studies, NMR spectroscopy, and other calculations. The stereochemical complexity is determined by the different isomers formed through complexation of the metal to one or other face of each of the three olefins involved. The palladacyclopropane formulation of the palladium-olefin interaction offers a clear picture of the stereogenicity of the olefin carbon atoms that are complexed to the metal. The energetically favorable isomers were identified in the solid-state and in solution by performing X-ray diffraction and NMR spectroscopic analysis, respectively.
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Transition metal-mediated intramolecular [2+2+2] cycloisomerizations of cyclic triynes and enediynes.
[reaction: see text] Nitrogen-containing 15-membered triacetylenic macrocycles known as 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triynes (1) and enediynic macrocycles called 1,6,11-tris(arylsulfonyl)-1,6,11-triazacyclopentadeca-3-ene-8,13-diynes (4 and 5) were satisfactorily prepared. [2+2+2] cycloisomerization processes catalyzed by transition metals were tested in the above-mentioned macrocycles. Readily available and familiar cyclotrimerization precatalysts were examined for efficiency. Among them, the RhCl(CO)(PPh(3))(2) complex was found to catalyze the cycloisomerization reaction giving the desired cycloadducts in high yields.
Alkynes↗
Ionic and covalent copper(II)-based catalysts for Michael additions. The mechanism.
Cu(SbF6)2-AdamBox and copper(II) bis-(5-tert-butylsalicylaldehydate) catalyze the Michael addition in neutral media. Mechanistic studies, based on UV-vis, IR, and electrospray ionization mass spectrometry (ESI-MS), suggest that copper enolates of the beta-dicarbonyl formed in situ are the active nucleophilic species.
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Superhydrophobic silica aerogels by fluorination at the gel stage.
Superhydrophobic silica aerogels are obtained by surface modification of standard silica gels prepared by a two-step process with a heavily fluorinated silyl chloride followed by supercritical evacuation of the solvent.
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First Heck reaction with arenediazonium cations with recovery of Pd-triolefinic macrocyclic catalyst.
The air- and moisture-stable phosphine-free palladium(0) complex 1 is a highly active and recoverable catalyst for Heck olefination of aryl diazonium tetrafluoroborates. The reactions were performed under aerobic conditions at room temperature to give the coupling products in excellent yields. [reaction: see text]
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Formation of carbon--carbon bonds under catalysis by transition-metal nanoparticles.
This Account presents the fast-growing field of catalysis by transition metal nanoparticles, its present situation concerning scope and limitations, as well as future prospects. The Account is limited to reactions involving carbon-carbon bond formation.
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Palladium nanoparticles stabilised by polyfluorinated chains.
Palladium nanoparticles can be prepared by reduction of palladium(II) chloride in the presence of different compounds featuring long perfluorinated carbon chains.
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Electrospray Ionization Mass Spectrometry Detection of Intermediates in the Palladium-Catalyzed Oxidative Self-Coupling of Areneboronic Acids.
Several intermediates of the oxidative coupling of areneboronic acids to afford biaryls have been identified by electrospray ionization mass spectrometry. Knowledge has been gained about the steps occurring after the biaryl formation and leading to the recovery of the catalytic species.
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Palladium(0)-Catalyzed Allylation of Highly Acidic and Nonnucleophilic Anilines. The Origin of Stereochemical Scrambling When Using Allylic Carbonates.
Acidic anilines such as diphenylamine, phenothiazine, and nitroanilines are efficiently allylated under palladium catalysis using allyl carbonates as allylating reagents. A stereochemical study of the reactions of ethyl cis-5-methyl-2-cyclohexenylcarbonate with 4-nitro- and 2,4-dinitroaniline was performed. Bidentate phosphines as stabilizing ligands gave clean retention of configuration whereas triphenylphosphine permitted cis-trans isomerization of the allylic carbonate, the allylation reactions occurring under Curtin-Hammet preequilibrium conditions.
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(1-(Dimethylamino)-2-(diphenylphosphino)ethane)(eta(3)-1-arylallyl)palladium Tetrafluoroborates. Preparation, Isomeric Equilibria, and Correlations of NMR Chemical Shifts with Hammett Substituent Constants.
13C NMR differences of chemical shifts (delta(X) - delta(H)) of allyl carbon atoms in a series of trans-(1-(diphenylphosphino)-2-(dimethylamino)ethane)(eta(3)-1-arylallyl)palladium tetrafluoroborates, X ranging from NO(2) to OMe, correlate very well with sigma Hammett constants for C-1 and with sigma(+) for C-3, this carbon atom being in a trans relationship with the positively charged nitrogen atom.
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