References of "Demonceau, Albert"
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See detailMicrowave-Enhanced Ruthenium Catalysed Atom Transfer Radical Additions
Richel, Aurore ULg; Leclerc, Alain; Demonceau, Albert ULg et al

Poster (2005)

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See detailElectrochemistry as a correlation tool candidate with catalytic activities in ruthenium(II)-catalysed atom transfer radical polymerisation ?
Richel, Aurore ULg; Tutusaus, Oscar; Viñas, Clara et al

in Polymer Preprints (2005), 46(2), 227-228

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See detailControlled radical polymerisation of vinyl monomers catalysed by ruthenium N-heterocyclic carbene complexes
Delfosse, Sebastien; Richel, Aurore ULg; Borguet, Yannick ULg et al

in Matyjaszewski, Krzysztof (Ed.) Controlled/living radical polymerization. From synthesis to materials (2005)

N-heterocyclic carbene (NHC)-modified ruthenium catalysts of type [RuCl2(p-cymene)(NHC)] (NHC = substituted 2,3-dihydro-1H-imidazol-2-ylidenes: 1,3-Mes2-4,5-Me2, 1,3-Mes2-4,5-H2, 1,3-Mes2-4,5-Cl2, 1,3-Cy2 ... [more ▼]

N-heterocyclic carbene (NHC)-modified ruthenium catalysts of type [RuCl2(p-cymene)(NHC)] (NHC = substituted 2,3-dihydro-1H-imidazol-2-ylidenes: 1,3-Mes2-4,5-Me2, 1,3-Mes2-4,5-H2, 1,3-Mes2-4,5-Cl2, 1,3-Cy2-4,5-Me2, and 1,3-Cy2-4,5-H2; Mes = mesityl, Cy = cyclohexyl) were prepd. beforehand or in situ by combining the [RuCl2(p-cymene)] dimer with the imidazolium salt in presence of a base (e.g., t-BuOK, Cs2CO3, or Al(OiPr)3). The catalysts were then used in homogeneous atom transfer radical polymns. of Me methacrylate and styrene. The polymn. outcome was studied in dependence of catalyst (substitution pattern) and base. [less ▲]

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See detailCatalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing substituents
Sauvage, Xavier ULg; Tudose, Adriana; Delfosse, Sébastien et al

Poster (2005)

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See detailCatalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing substituents
Sauvage, Xavier ULg; Tudose, Adriana; Delfosse, Sébastien et al

Conference (2005)

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See detailMicrowave-assisted ruthenium-catalysed atom transfer radical reactions
Delfosse, Sébastien; Richel, Aurore ULg; Wei, H. et al

Conference (2005)

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See detailStereoselective synthesis of (E)-hydroxystilbenoids by ruthenium-catalyzed cross-metathesis
Ferre-Filmon, Karine; Delaude, Lionel ULg; Demonceau, Albert ULg et al

in European Journal of Organic Chemistry (2005), (15), 3319-3325

An efficient and highly stereoselective synthetic procedure is reported for the construction of symmetrical and unsymmetrical (E)-polymethoxystilbene and (E)-polyhydroxystilbene derivatives. The strategy ... [more ▼]

An efficient and highly stereoselective synthetic procedure is reported for the construction of symmetrical and unsymmetrical (E)-polymethoxystilbene and (E)-polyhydroxystilbene derivatives. The strategy rests on a cross-metathesis reaction catalyzed by stable, well-defined (alkylidene)ruthenium complexes, in particular the second-generation Grubbs catalyst [RuCl2(=CHPh)(SlMes)(PCY3)1 [SIMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]. The metathesis of unprotected phenolic styrenes is illustrated by the synthesis of the important phytoalexins (E)-3,4',5-trihydroxystilbene (resveratrol) and (E)-3,3',4,5'-tetrahydroxystilbene (piceatannol). (c) Wiley-VCH Verlag GmbH [less ▲]

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See detailControlled radical polymerization of vinyl monomers catalyzed by ruthenium N-heterocyclic carbene complexes
Demonceau, Albert ULg; Delfosse, Sébastien ULg; Richel, Aurore ULg et al

in Abstracts of Papers - American Chemical Society, National Meeting (2005), 230

As part of our program devoted to the development of new metal-NHC catalyst systems, we have launched a detailed investigation on the catalytic activity of ruthenium-p-cymene complexes bearing NHC ligands ... [more ▼]

As part of our program devoted to the development of new metal-NHC catalyst systems, we have launched a detailed investigation on the catalytic activity of ruthenium-p-cymene complexes bearing NHC ligands for the ring opening metathesis polymerization (ROMP) of cyclic olefins and for the ATRP of vinyl monomers. We report herein on the use for ATRP of [RuCl2(p-cymene)(NHC)] complexes generated in situ by combining the [RuCl2(p-cymene)]2 dimer with an imidazolium salt and a base such as potassium tert-butoxide, cesium carbonate or aluminum isopropoxide. [less ▲]

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See detailCatalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing side-groups
Tudose, Adriana; Sauvage, Xavier; Delfosse, Sébastien et al

Poster (2004, July)

Herein, we report preliminary results in olefin cyclopropanation, olefin metathesis, atom transfer radical reactions (ATRA and ATRP), and in the Suzuki coupling reaction when catalyst systems were ... [more ▼]

Herein, we report preliminary results in olefin cyclopropanation, olefin metathesis, atom transfer radical reactions (ATRA and ATRP), and in the Suzuki coupling reaction when catalyst systems were generated in situ from [RuCl2(p-cymene)]2 or Pd(OAc)2, and an imidazolium salt bearing nitrogen-containing substituents. [less ▲]

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See detailCatalytic methods for the synthesis of stilbenes with an emphasis on their phytoalexins
Ferre-Filmon, Karine; Delaude, Lionel ULg; Demonceau, Albert ULg et al

in Coordination Chemistry Reviews (2004), 248(21-24), 2323-2336

This review aims at summarizing the recent significant advances in catalytic methods available for the synthesis of stilbene and functionalized stilbenes with an emphasis on their phytoalexins. Most ... [more ▼]

This review aims at summarizing the recent significant advances in catalytic methods available for the synthesis of stilbene and functionalized stilbenes with an emphasis on their phytoalexins. Most strategies developed so far involve palladium-mediated coupling reactions. Among them, the Heck and Suzuki reactions stand out for their synthetic versatility and efficiency, but the Stille and Negishi reactions have also found useful applications. Palladium also served as a catalyst to convert Z-stilbenes into the corresponding E-isomers. Other transition metal promoted stilbene syntheses include the McMurry coupling of aldehydes and ketones and alkene cross metathesis. Because non transition metal catalyzed syntheses of hydroxystilbenes continue to attract a lot of attention, significant recent developments in this area are also reported. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailRuthenium-promoted radical processes toward fine chemistry
Delaude, Lionel ULg; Demonceau, Albert ULg; Noels, Alfred ULg

in Dixneuf, Pierre Henri; Bruneau, Christian (Eds.) Ruthenium catalysts and fine chemistry (2004)

A review. Ruthenium holds a prominent position among the many transition metals used in radical chem. The dichlorotris(triphenylphosphine) complex [RuCl2(PPh3)3] was the first active ruthenium-based ... [more ▼]

A review. Ruthenium holds a prominent position among the many transition metals used in radical chem. The dichlorotris(triphenylphosphine) complex [RuCl2(PPh3)3] was the first active ruthenium-based catalyst investigated for atom-transfer radical addn. processes and has found numerous applications in org. synthesis. Other catalytic systems that have been devised since include (1) neutral or cationic Grubbs-type complexes bearing an alkylidene fragment and either phosphine, N-heterocyclic carbene, or Schiff base ligands, (2) half-sandwich ruthenium complexes bearing a cyclopentadienyl, a pentamethylcyclopentadienyl, or an indenyl ligand, and (3) ruthenium complexes bearing anionic carborane-phosphine and dicarbollide ligands. Their activities are discussed and the predictive value of cyclic voltammetry in radical chem. is questioned. A related example of a ruthenium-catalyzed C-H hydroxylation reaction is also reported. [less ▲]

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See detailRuthenium N-heterocyclic carbene complexes: Versatile catalysts precursors for olefin metathesis, olefin cyclopropanation, and radical reactions
Demonceau, Albert ULg; Richel, Aurore ULg; Delfosse, Sébastien et al

Conference (2003, August)

N-heterocyclic carbenes are divalent carbon species, which are commonly used as neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are ... [more ▼]

N-heterocyclic carbenes are divalent carbon species, which are commonly used as neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are better s-donors and they form stronger bonds to metal centres than most phosphines. Their electronic and steric properties are liable to ample modification simply by varying the substituents on the nitrogen atoms. Therefore, N-heterocyclic carbenes constitute a promising new class of ligands available for catalyst engineering and fine tuning, and a great deal of attention has been paid to them recently. We found that the 18-electron complex RuCl2(p-cymene)(PCy3) was a versatile and efficient promoter for the ring-opening metathesis polymerisation of both strained and low-strain cyclic olefins when activated by a suitable carbene precursor such as trimethylsilyl-diazomethane. RuCl2(p-cymene)(PCy3) was also an excellent catalyst for ATRP (Atom Transfer Radical Polymerisation) of methyl methacrylate and styrene. Here, we present preliminary results obtained in olefin metathesis, olefin cyclopropanation, and radical reactions (ATRP and Kharasch addition) when tricyclohexylphosphine was substituted by an N-heterocyclic ligand. [less ▲]

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See detailRuthenium alkylidenes: a new class of catalysts for Kharasch addition and controlled radical polymerisation of vinyl monomers
Delfosse, Sébastien; Richel, Aurore ULg; Peters, Christelle et al

Poster (2003, May)

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See detailRuthenium alkylidenes: a new class of catalysts for Kharasch addition and controlled radical polymerisation of vinyl monomers
Delfosse, Sébastien; Richel, Aurore ULg; Demonceau, Albert ULg et al

Poster (2003, May)

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst ... [more ▼]

Air-stable and readily available ruthenium benzylidene complexes of the general type (RuCl2 (=CHPh)(L)(L')) (L, L' = P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) constitute a new class of catalyst precursors for atom transfer radical addition (ATRA, also called Kharasch addition) and atom transfer radical polymerisation (ATRP) of methyl methacrylate and styrene, and provide an unprecedented example for the involvement of ruthenium alkylidenes in radical reactions. They promote the addition of carbon tetrachloride to methyl methacrylate and styrene in moderate to high yield (Table 1). They also promote the polymerisation of methyl methacrylate and styrene in a controlled way with good to excellent yields (Table 2). The ligands L (P(cC5H9)3, PCy3 and/or a N-heterocyclic carbene) play a particularly important role in determining the rate of the polymerisation. A similarly pronounced influence is exerted by the substituents on the N-heterocyclic carbene. Our results indicate that: 􀀀 The catalysts decompose quickly under ATRA and ATRP conditions; 􀀀 Polymerisations are mediated by both (RuCl2(=CHPh)(L)(L')) complexes and ruthenium species bereft of the benzylidene moiety. [less ▲]

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See detailDual activity of ruthenium catalysts in controlled radical reactions and olefin metathesis
Delaude, Lionel ULg; Filmon, Karine; Delfosse, Sébastien et al

Conference (2003, May)

The catalytic activity of five ruthenium-arene complexes of the RuCl2(p-cymene)L type was investigated in controlled radical reactions and olefin metathesis. The ligands L were stable Nheterocyclic ... [more ▼]

The catalytic activity of five ruthenium-arene complexes of the RuCl2(p-cymene)L type was investigated in controlled radical reactions and olefin metathesis. The ligands L were stable Nheterocyclic carbenes (NHCs) derived from imidazol-2-ylidene. They differed by the nature of the substituents on the nitrogen atoms (R1) and on the carbon-carbon double bond (R2) of the heterocyclic ring. Thus, R1 was either the mesityl or the cyclohexyl group, and R2 included methyl, hydrogen, or chloro substituents.The complexes were tested as initiators for the Atom Transfer Radical Addition (ATRA) of carbon tetrachloride to methyl methacrylate and styrene, for the Atom Transfer Radical Polymerization (ATRP) of methyl methacrylate and styrene, and for the Ring-Opening Metathesis Polymerization (ROMP) of cyclooctene. Some species displayed a dual activity and promoted both olefin metathesis and ATRP. [less ▲]

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See detailNew ruthenium catalysts bearing N-heterocyclic carbene ligands for ATRP
Sauvage, Xavier ULg; Richel, Aurore ULg; Delfosse, Sébastien et al

Poster (2003, May)

Stable nucleophilic N-heterocyclic carbenes (NHCs) are neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are better s- donors and they form ... [more ▼]

Stable nucleophilic N-heterocyclic carbenes (NHCs) are neutral, two-electron ligands with a negligible p-back-bonding tendency. They behave as phosphine mimics, yet they are better s- donors and they form stronger bonds to metal centers than most phosphines. Their electronic and steric properties are liable to ample modification simply by varying the substituents on the nitrogen atoms. Therefore, NHCs constitute a promising new class of ligands available for catalyst engineering and fine-tuning. We found that the 18-electron complex RuCl2(p-cymene)(PCy3) was a versatile and efficient promoter for ring-opening metathesis polymerization of both strained and low-strain cyclic olefins when activated by a suitable precursor such as trimethylsilyldiazomethane. This complex was also an excellent catalyst for ATRP (Atom Transfer Radical Polymerization) of MMA and styrene. In this poster, we present preliminary results obtained in olefin metathesis and in radical reactions (ATRP and Kharasch addition) when tricyclohexylphosphine was substituted by an N-heterocylic carbene ligand. [less ▲]

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See detailAtom Transfer Radical Polymerisation (ATRP) and Kharasch addition mediated by titanium-ruthenium bimetallic systems
Richel, Aurore ULg; Delfosse, Sébastien; Demonceau, Albert ULg et al

Poster (2003)

Numerous studies have been directed towards the synthesis of early-late heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their ... [more ▼]

Numerous studies have been directed towards the synthesis of early-late heterobimetallic complexes. Surprisingly, only few reports have been reported about their catalytic behaviour. However, their potential in homogeneous catalysis is enormous. Indeed, a co-operative work by the two metal centres in the complex may lead to new catalytic systems with unique reactivity. <br /> <br />The Dijon’s team has concentrated their efforts on the synthesis and study of heterobimetallic complexes in which both metal fragments are known for their catalytic activity. Titanocenes are of considerable interest as catalysts for the polymerisation of a-olefins. The catalytic performance of RuCl2(arene) complexes (1) has been demonstrated in different reactions, including olefin metathesis and atom transfer radical polymerisation (ATRP). In attempts to examine such type of catalytic systems, complexation of bent titanocene metallo-ligands by the [RuCl2(p-cymene)]2 dimer is currently investigated. [less ▲]

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See detailTuning of ruthenium N-heterocyclic carbene catalysts for ATRP
Delaude, Lionel ULg; Delfosse, Sébastien ULg; Richel, Aurore ULg et al

in Chemical Communications (2003), (13), 1526-1527

Depending on the substituents, R-1 and R-2, ruthenium(II) - p-cymene complexes bearing N-heterocyclic carbene ligands are either efficient catalysts for the well-controlled atom transfer radical ... [more ▼]

Depending on the substituents, R-1 and R-2, ruthenium(II) - p-cymene complexes bearing N-heterocyclic carbene ligands are either efficient catalysts for the well-controlled atom transfer radical polymerisation of methyl methacrylate and styrene, or promote a redox-initiated free-radical process. [less ▲]

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