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Lega M.,University of Naples Federico II | Lega M.,Consorzio Interuniversitario Of Reattivita Chimica talisi | Margalef J.,Rovira i Virgili University | Ruffo F.,University of Naples Federico II | And 3 more authors.
Tetrahedron Asymmetry | Year: 2013

A series of glucopyranoside phosphite-pyridine ligands have been applied in the metal-catalyzed allylic substitution and conjugate 1,4-addition reactions of several substrate types. We have been able to identify ligands that provided promising enantioselectivities in the Pd-catalyzed intermolecular allylic substitution of cyclic substrates (ee's up to 86%) and desymmetrization (ee's up to 94%) and in the Cu-catalyzed conjugate addition of challenging aliphatic enones (ee's up to 90%). © 2013 Elsevier Ltd. All rights reserved. Source


Margalef J.,Rovira i Virgili University | Lega M.,University of Naples Federico II | Lega M.,Consorzio Interuniversitario Of Reattivita Chimica talisi | Ruffo F.,University of Naples Federico II | And 3 more authors.
Tetrahedron Asymmetry | Year: 2012

Eight (biaryl)phosphite/pyridine ligands 1-2a-d have been prepared by the modular functionalization of positions C-2 and C-3 of two d-glucopyranoside backbones. The chiral ligands were examined in the iridium-catalyzed asymmetric hydrogenation of poorly functionalized alkenes, as a function of the relative position of the coordinating groups and the geometric properties of the biaryl phosphite moieties. Enantiomeric excesses of up to 90% were achieved in the hydrogenation of E-2-(4-methoxyphenyl)-2-butene by using 1a and 1c, which seemingly combine the beneficial effect of the phosphite at the 2-position with the matching (R ax)-configuration of their encumbered biaryl substituents. The results of the hydrogenation of more challenging substrates, such as Z-trisubstituted alkenes, alkenes with a neighboring polar group or demanding 1,1-di-substituted alkenes, generally confirmed this trend, and in some significant cases, the chiral hydrogenated products were isolated with ees of 65-79%. ©2012 Elsevier Ltd. Source


Benessere V.,University of Naples Federico II | De Roma A.,Istituto Zooprofilattico Sperimentale del Mezzogiorno | Del Litto R.,University of Naples Federico II | Lega M.,University of Naples Federico II | And 3 more authors.
European Journal of Organic Chemistry | Year: 2011

The straightforward design of a new library of chiral ligands (elpanphos) based on β-1,2-D-glucodiamine is described, which represents the enantiomeric counterpart of the naplephos library. In this guise, two representative ligands have been successfully applied in the Pd-catalyzed desymmetrization of meso-cyclopent-2-ene-1,4-diol, which leads to the expected enantiomer within short times and with high ees in both traditional and unconventional solvents. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Lega M.,University of Naples Federico II | Lega M.,Consorzio Interuniversitario Of Reattivita Chimica talisi | Lega M.,KTH Royal Institute of Technology | Figliolia R.,University of Naples Federico II | And 4 more authors.
Tetrahedron | Year: 2013

The elpaN-Py family of ligands, which represents a subset of the elpaN-type library based on d-glucose, is described. The ligands are structural analogs of the privileged bis(pyridine-2-carboxamides) derived from trans-1,2- diaminocyclohexane, and differ for the type of substitution in the coordinating functions present in positions 1 and 2. Their ability to induce high enantioselectivity in asymmetric allylic alkylations promoted by molybdenum under microwave irradiation has been successfully demonstrated, starting from both a linear (ee up to 99%) and a branched substrate (ee up to 96%). The multifunctional nature of the sugar scaffold was exploited for the preparation of a polar ligand, through deprotection of the hydroxyl groups in positions 3, 4 and 6. In this version, it was possible to verify the performance in catalysis in alternative solvents, such as ionic liquids and water. © 2013 Elsevier Ltd. All rights reserved. Source


Bismuto A.,University of Naples Federico II | Cucciolito M.E.,University of Naples Federico II | Cucciolito M.E.,Consorzio Interuniversitario Of Reattivita Chimica talisi | Ruffo F.,University of Naples Federico II | And 4 more authors.
Phosphorus, Sulfur and Silicon and the Related Elements | Year: 2015

A detailed optimization of the catalytic environment for the oxidation of sulfides promoted by Mn(salen)/H2O2 systems is proposed. The experimental setup is demonstrated to be active towards different substrates, providing TOFs up to 9300 h-1, which are among the highest reported for homogeneous catalysts employed in sulfoxidation reactions. Copyright © 2015 Taylor & Francis Group, LLC. Source

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