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Antoniotti S.,University of Nice Sophia Antipolis | Dalla V.,CNRS Organic and Macromolecular Chemistry Research Unit | Dunach E.,University of Nice Sophia Antipolis
Angewandte Chemie - International Edition | Year: 2010

The continuously increasing need for novel and selective methods in organic synthesis to aid drug discovery and to address environmental concerns is a constant source of stimulation to develop novel and more efficient reaction systems. This has often resulted in a focus on transition metals, ligands, and additives, with much less attention paid to the counterion(s) of the metal cation. Recently, metal salts with one or more triflimidate counterion(s) have appeared as a unique class of catalysts that display outstanding σ- and π-Lewis acid character. The highly delocalized nature of the triflimidate counterion, combined with its high steric hindrance results in virtually no nucleophilic behavior and an extremely high positive charge density on the metal cation, thus enhancing its Lewis acid character. Consequently, these metal triflimidates often outperform their metal halide or triflate analogues. This Review describes general methods for the preparation of metal triflimidate salts and their use as catalysts. Worth its salt: The triflimidate anion, by virtue of its highly delocalized charge and steric hindrance, enhances the electrophilic character of the metal center and, therefore, its Lewis acidity. In most cases, triflimidate catalysts are superior to triflates or other salts. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Pesquet A.,CNRS Organic and Macromolecular Chemistry Research Unit | Othman M.,CNRS Organic and Macromolecular Chemistry Research Unit
Tetrahedron Letters | Year: 2013

A novel approach to diversely spirocyclic isoindoles has been developed by using N-acyliminium/ring-closing metathesis strategy. Spirocyclization precursors, diolefinic, and enyne spiro-fused-isoindole derivatives have been obtained by a regioselective reduction of the spiro-imide compounds, followed by the allylation of the N-acyliminium intermediates (generated from the acetoxylactam compounds). Ruthenium catalyzed ring-closing metathesis of the above unsaturated derivatives provided novel spiroisoindoles. © 2013 Elsevier Ltd. All rights reserved. Source

Comesse S.,CNRS Organic and Macromolecular Chemistry Research Unit | Martel A.,University of Maine, France | Daich A.,CNRS Organic and Macromolecular Chemistry Research Unit
Organic Letters | Year: 2011

A totally new acid-free domino process to access highly functionalized bicyclic γ- and δ-lactams starting from commercially available and inexpensive ethoxymethylene derivatives is reported. Mechanisms elucidated by computational calculations led to new reaction conditions that boosted the yields up to 3.5 times higher. © 2011 American Chemical Society. Source

Savary G.,CNRS Organic and Macromolecular Chemistry Research Unit | Grisel M.,CNRS Organic and Macromolecular Chemistry Research Unit | Picard C.,CNRS Organic and Macromolecular Chemistry Research Unit
Colloids and Surfaces B: Biointerfaces | Year: 2013

This study deals with the impact of emollients on the spreading properties of cosmetic products using a combined sensory-instrumental approach. To that purpose, three esters and one silicone were selected and incorporated separately into an oil phase. Different cosmetic o/w emulsions were then prepared with these different oil phases. Both of them were analyzed by instrumental techniques and in vivo sensory analyses. A significant effect of the emollient used was established in emulsions and in oil phases as well. Concerning emulsions, results reveal a clear correlation between in vivo spreading evaluation and friction coefficient parameters measured by texture analyzer, despite a fairly low correlation coefficient (Pearson coefficient = -0.78). Concerning oil phases, characterization of spreading was done by monitoring the contact angle relaxation of a drop of solution after deposition on a flat PMMA surface whereas sensory procedure was based on spontaneous spreading of oil phases onto the skin. Finally, good correlations between in vivo sensory analysis and instrumental measurements of both oils and emulsions were found, thus promising the possible development of predictive tools to evaluate spreadability. © 2012 Elsevier B.V. Source

Othman R.B.,CNRS Organic and Macromolecular Chemistry Research Unit | Othman R.B.,Gafsa University | Affani R.,CNRS Organic and Macromolecular Chemistry Research Unit | Tranchant M.-J.,CNRS Organic and Macromolecular Chemistry Research Unit | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2010

(Chemical Equation Presentation) Atom-economical: Unmodified hemiN,O-acetals are used in a catalytic, highly efficient α- amidoalkylation of a broad range of carbon-centered nucleophiles, including silicon-based components, active methylene derivatives, electron-rich arenes, and even simple ketones (see scheme). The reactions proceed in a highly efficient manner and typically require only 1 mol% of the Lewis super-acidic reagent Sn(NTf2)4 as the catalyst. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA. Source

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