Luis Velasco
National Autonomous University of Mexico
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Featured researches published by Luis Velasco.
Organic Letters | 2009
Laura Rubio-Pérez; F. Javier Pérez-Flores; Pankaj Sharma; Luis Velasco; Armando Cabrera
The application of air stable preformed [(R)-BINAP]PdBr2, [(S)-BINAP]PdBr2, [(R)-Tol-BINAP]PdBr2, and [(S,S)-CHIRAPHOS]PdBr2 complexes in the one-pot asymmetric reductive amination of various carbonyl compounds, leading to chiral amines in very good yields with high enantioselectivities (<99% ee), is reported.
Synthetic Communications | 1992
F. Delgado; Andrés C. Cano; Olivia Maya García; J. Alvarado; Luis Velasco; Cecilio Alvarez; H. Rudler
Abstract An efficient and simple procedure for the direct conversion of aromatic Aldehydes into the corresponding nitriles with hydroxylamine hydrochloride and a Mexican Bentonite via infrared or microwave irradiation.
Journal of Molecular Catalysis A-chemical | 1995
Armando Cabrera; Jorge Peon; Luis Velasco; René Miranda; Alejandro Salmón; Manuel Salmón
The catalytic synthesis of substituted 1,3-dioxolanes, 1,4-dioxanes, 9-crown-3, 12-crown-4 and 15-crown-5 ethers, from alkyl oxiranes and a montmorillonite type clay is discussed.
Journal of Molecular Catalysis | 1992
Armando Cabrera; D. Vázquez; Luis Velasco; Manuel Salmón; J. L. Arias
Abstract The coupling reaction of oxiranes with carbonyl compounds to produce 1,3-dioxolanes was promoted by catalytic amounts of a bentonitic clay. The product yield was found to be dependent on the catalyst, the reaction temperature and the reagent concentrations. A kinetic study performed with acetone and ethylene oxide showed a first-order dependence in both reagents. Other experiments made with different epoxides, carbonyl compounds and catalysts are also discussed.
Synthetic Communications | 1998
Armando Cabrera; N. Rosas; Pankaj Sharma; R. Le Lagadec; Luis Velasco; Manuel Salmón; J. L. Arias
Abstract An example of hydrodimerization of some cyclic enones by SmI2/THF system is described. The use of HMPA (hexamethyl phosphoramide), as a copromoter in the system, improves the yield of dimerized products. The X-ray structure of one of these dimers, bis-3,3′(3,5,5-trimethyl cyclohexanone), is also reported.
Journal of Molecular Catalysis A-chemical | 1997
Armando Cabrera; Pankaj Sharma; José Luis Garcı́a; Luis Velasco; F. Javier Pérez; JoséLuis Arias; Noe Rosas
Abstract The catalytic system Co 2 (CO) 8 /diphos/THF-H 2 O, an effective catalyst for carbonylation reactions, was studied for simultaneous hydrocarboxylation and hydroformylation of cyclohexene. Using this catalytic system, cyclohexene with CO and H 2 O gives cyclohexenecarboxaldehyde and cyclohexenecarboxylic acid as the main reaction products and cyclohexylmethanol as by-product. The catalytic reaction shows that the hydrocarboxylation/hydroformylation ratio is dependent on water concentration and the reaction temperature. The effects of the other reaction variables such as CO pressure and catalyst concentration were also examined.
Polyhedron | 1998
Armando Cabrera; Manuel Salmón; Noe Rosas; Javier Pérez-Flores; Luis Velasco; Georgina Espinosa-Pérez; J. L. Arias
Abstract A positive-ion Fast Atom Bombardment (FAB) study was performed to determine the structure of samarium(III) triiodine complex (I). Collision Induced Dissociation (CID) and High Resolution Mass Spectrometry were used to establish the fragmentation pattern of the C24H72O4N12P4I3Sm compound. The structure of (I) was confirmed by X-ray analysis.
Journal of The Chemical Society-perkin Transactions 1 | 1998
Armando Cabrera; Ronan Le Lagadec; Pankaj Sharma; J. L. Arias; Rubén A. Toscano; Luis Velasco; Rubén Gaviño; Cecilio Alvarez; Manuel Salmón
Samarium(II) iodide is a strong one-electron transfer reducing agent, and is effective for the cyclo- and hydrodimerization of cyclic and non-cyclic α,β-unsaturated ketones. The title dimers can easily be prepared in good yields at room temperature under neutral conditions, using two-mole equivalent of SmI2 per mole of starting substrate. The reaction is stereocontrolled. The absence of an alcohol as a proton source is essential in the process and the use of HMPA as a copromoter improves the yield of dimeric products, making the reaction regioselective over the competitive CC double bond reduction. The crystal structures of some of the dimeric derivatives are reported. When η2- or η4-iron-coordinated α,β-unsaturated ketones are used as substrates, the reaction gives mainly the 1,4-reduced products.
Transition Metal Chemistry | 2002
Rodolfo Álvarez; Armando Cabrera; Georgina Espinosa-Pérez; Simón Hernández-Ortega; Luis Velasco; Baldomero Esquivel
The synthesis and characterization of the pentacoordinated butanoylsalophencobalt(III) compound, including X-ray analysis, are described. The chemical shift in the 13C-n.m.r. of the carbonyl carbon was determined by means of an HMBC experiment. Collision induced dissociation (CID) and high resolution mass spectrometry were used to establish the fragmentation pattern of the CoC24H21N2O3 compound. X-ray diffraction analysis shows the presence of two conformations for the acylsalophen ligand system in the same monocrystal, as well as two different OċċċH–C hydrogen bonds with unusual interactions.
Catalysis Science & Technology | 2014
Armando Cabrera; Pankaj Sharma; F. Javier Pérez-Flores; Luis Velasco; J. Luis Arias; Laura Rubio-Pérez
An efficient preformed chiral palladium catalyzed direct diastereo- and enantioselective reductive amination of un- and substituted cycloaliphatic ketones with primary aryl amines has been developed.