Selective synthesies of 2 types of N-heterocycles through heterogeneous multi-catalysis.

internationa

Carbonylative Sonogashira Coupling in the Synthesis of Ynones: A Study of "Boomerang" Phenomena

BIOVERT+MGE:LDJThe behaviour of several organophosphino-palladium complexes immobilized on mesoporous silica during the palladium-catalyzed synthesis of propynone by carbonylative Sonogashira coupling was studied, particularly concerning leaching/redeposition phenomena. The results demonstrated that this cross-coupling reaction is catalyzed by soluble species. Furthermore, it is shown that the palladium leaching is not initiated by the oxidative addition step but rather by palladium-decoordination from grafted ligand. Despite this decoordination, catalyst performance after recycling is adequate. Additionally, several parameters linked either to catalyst preparation or reaction procedures were shown to reduce leaching allowing one to achieve metal contamination levels close to the recommendation of the European Agency for the Evaluation of Medicinal Products. Interestingly, this heterogeneous palladium-catalyzed procedure is fully selective toward the formation of ynones, allowing the preparation of various target compounds

Matériaux hybrides "complexes de palladium@silice mésoporeuse" pour l'obtention sélective de N-hétérocycles carbolylés

nationa

Heterogeneous metallo-organocatalysis for the selective one-pot synthesis of 2-benzylidene-indoxyl and 2-phenyl-4-quinolone

5 Genelot, Marie Dufaud, Veronique Djakovitch, LaurentOne-pot tandem heterogeneously catalyzed procedures for the selective synthesis of 2-benzylidene-indoxyl and 2-phenyl-4-quinolone have been developed. For this purpose, heterogeneous palladium-, amine-, and phosphine-catalysts were prepared by post-synthetic grafting onto SBA silica. The state of the hybrid materials was characterized using a wide variety of molecular and solid-state techniques. These materials exhibit high activities as 2-benzylidene-indoxyl was obtained in 81% yields through {[Pd]@SBA-15+PPh3} catalysis while 2-phenyl-4-quinolone was prepared by a fully heterogeneous if {[Pd]@SBA-15+[AMINE]@SBA-3} protocol in 61-75% isolated yield. For the later, we demonstrated that the catalysts mixture could be reused up to three runs without strong deactivation. (C) 2010 Elsevier Ltd. All rights reserved

Article sur le declassement et l'assainissement des installations nucleaires

International audienceArticle decrivant l-etat de l-art sur la conduite des operations d-assainissement, de demantelement et de declassement des installations nucleaires

Optimised procedures for the one-pot selective syntheses of indoxyls and 4-quinolones by a carbonylative Sonogashira/cyclisation sequence

Genelot, Marie Bendjeriou, Anissa Dufaud, Veronique Djakovitch, LaurentA selective one-pot synthesis of carbonyl-containing N-heterocyclic compounds has been developed using a carbortylative Sonogashira/cyclisation sequence. Various catalytic protocols were studied (CO pressure, temperature, catalyst identity, base and substrate/catalyst ratio) with the objective of obtaining selectively either indoxyl or 4-quinolone products. The origin of the selectivity toward the 5-or 6-membered ring compounds was explained through the respective role of the various catalytic species involved, whether they are organic or metallic. The non-cyclic common intermediate was selectively prepared using [PdCl2(dppp)] as catalyst. By using a two-step multi-catalysis, i.e. {[Pd]+HNEt2}, 4-quinolones were obtained whereas with a tandem catalysis, i.e. {[Pd]/PR3), indoxyls were synthesised. (C) 2009 Elsevier B.V. All rights reserved

Palladium-based innovative catalytic procedures: Designing new homogeneous and heterogeneous catalysts for the synthesis and functionalisation of N-containing heteroaromatic compounds

Batail, Nelly Genelot, Marie Dufaud, Veronique Joucla, Lionel Djakovitch, Laurent 9th Congress on Catalysis Applied to Fine Chemicals (CAFC9) SEP 13-16, 2010 Zaragoza, SPAIN Spanish Natl Res Council (CSIC), Univ Zaragoza, Govt AragonN-containing heteroaromatics, particularly those owning an indole or quinolone substructure, are found in numerous natural or synthetic alkaloids of biological and pharmaceutical relevance. Therefore, various synthetic methodologies have been reported to access these backbones. The most advanced procedures use transition metal catalysts, usually as soluble (homogeneous) materials. In this short review article, we report our recent developments devoted to improving current catalytic pathways toward greener processes and to designing new heterogeneous Pd-based catalysts. The latter approach brings as main advantages low metal contamination and recyclability. The potential of these developments is demonstrated through the selective synthesis, as well as the functionalisation, of (NH)-indoles, quinolones, indoxyls or stilbenes. (C) 2011 Elsevier B.V. All rights reserved

Palladium complexes grafted onto mesoporous silica catalysed the double carbonylation of aryl iodides with amines to give alpha-ketoamides

BIOVERT+MGE:NVI:ABN:PJA:LDJA promising route for the double carbonylation of aryl iodide derivatives with secondary and primary amines to produce alpha-ketoamides is described using covalently immobilized palladium complexes on SBA-15 silica. Adequate adjustments of the different reaction parameters (temperature, CO pressure, nature of base, solvent, substrate...) to achieve optimal catalyst performance were made using PdCl2(PPh2)(2)@SBA-15 as catalytic system. High conversions (up to 80%) and excellent selectivities (up to 96%) for the double carbonylated alpha-ketoamide products were obtained using K2CO3 as base, MEK or DMF as solvent and a 1 mol% [Pd] catalyst. We also demonstrated that two other palladium hybrid mesoporous materials can be alternatively used, namelyPdCl(2)(PCy2)(2)@SBA-15 and PdCl2(PNP)@SBA-15, without loss of activity and selectivity. Finally, catalyst recycling of PdCl2(PPh2)(2)@SBA-15 showed that the catalyst could be reused for up to 3 cycles without affecting catalyst performance