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Egger L.,University of Geneva | Tortoreto C.,University of Geneva | Achard T.,University of Geneva | Monge D.,University of Seville | And 4 more authors.
Advanced Synthesis and Catalysis | Year: 2015

(Cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate [CpRu(CH3CN)3][PF6] in combination with pyridine-hydrazone ligands efficiently catalyzes the asymmetric decarboxylative allylic rearrangement of allyl aryl carbonates. Formation of C-O bonds with high regio- and enantioselectivity ratios (up to 95:5 and 98% ee) is obtained. Good stereocontrol of the pseudotetrahedral geometry of the CpRu moiety is achieved by the hydrazone ligand and its "electron-poor" nature is evidenced through the epimerization of the hexacoordinated TRISPHAT-N anion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ramirez-Lopez P.,Instituto Investigaciones Quimicas Csic Us | Ros A.,Instituto Investigaciones Quimicas Csic Us | Estepa B.,University of Seville | Fernandez R.,University of Seville | And 3 more authors.
ACS Catalysis | Year: 2016

The Pd-catalyzed enantioselective C-P cross-coupling between racemic, configurationally stable heterobiaryl triflates and trialkylsilyldiaryl(dialkyl)phosphines has been used for the synthesis of several families of enantiomerically enriched heterobiaryl phosphines including QUINAP, PINAP, and QUINAZOLINAP analogues, which can be performed with good yields and enantioselectivities using JOSIPHOS-type bidentate phosphines. The strategy relies on two key assumptions: (I) The N atom of the heterocycle is a better ligand than triflate, and upon oxidative addition, it incorporates into the coordination sphere of the PdII center to form cationic cyclic intermediates. (II) The geometry of the palladacycle results in a widening of the angles involved in the stabilization of the stereogenic axis, facilitating a fast interconversion of diastereomeric structures and, hence, a dynamic kinetic C-P cross-coupling reaction. These starting hypotheses are supported by experimental and computational studies. © 2016 American Chemical Society.

Ros A.,Instituto Investigaciones Quimicas Csic Us | Lopez-Rodriguez R.,Instituto Investigaciones Quimicas Csic Us | Estepa B.,University of Seville | Alvarez E.,Instituto Investigaciones Quimicas Csic Us | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

The use of hemilabile pyridine-hydrazone N,N-ligands allows the highly selective Ir-catalyzed ortho,ortho'-directed diborylation of aromatic N,N-dimethylhydrazones in near-quantitative yields. One-pot sequential Suzuki-Miyaura cross-coupling with different aryl bromides provides a short entry to unsymmetrically substituted 2,6-diarylbenzaldehyde derivatives. © 2012 American Chemical Society.

Crespo-Pena A.,Instituto Investigaciones Quimicas Csic Us | Monge D.,University of Seville | Martin-Zamora E.,University of Seville | Alvarez E.,Instituto Investigaciones Quimicas Csic Us | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

The dual activation of α-keto esters and formaldehyde tert-butyl hydrazone by BINAM-derived bis-ureas is the key to achieve high reactivity and excellent enantioselectivities in nucleophilic addition (formal carbonyl-ene reaction) to functionalized tertiary carbinols. Ensuing high-yielding diazene-to-aldehyde tranformations and subsequent derivatizations provides a direct entry to a variety of densely functionalized products. © 2012 American Chemical Society.

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