   Synthesis of stilbenoids via the Suzuki-Miyaura reaction catalysed by palladium N-heterocyclic carbene complexes; ; Sauvage, Xavier  et alin Journal of Molecular Catalysis A: Chemical (2006), 257(1-2), 158-166 The Suzuki-Miyaura reaction of aryl halides with trans-2-phenylvinylboronic acid using a series of related in situ generated N-heterocyclic carbene palladium(II) complexes was studied in order to evaluate ... [more ▼] The Suzuki-Miyaura reaction of aryl halides with trans-2-phenylvinylboronic acid using a series of related in situ generated N-heterocyclic carbene palladium(II) complexes was studied in order to evaluate the effect of ligand structure and electronics on the catalytic activity and to investigate the nature of the catalyst species. The nature of the substituents of the carbene ligand was found to be critical. Specifically, the presence of alkyl groups on the ortho positions of the phenyl substituents was a requisite for obtaining the most efficient catalyst systems. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 58 (3 ULg)Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium-arene catalysts for olefin metathesis and cyclopropanation; Demonceau, Albert ; Delaude, Lionel in Journal of Organometallic Chemistry (2006), 691(24-25), 5356-5365 Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,.6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by ... [more ▼] Five imidazol(in)ium-2-carboxylates bearing cyclohexyl, mesityl, or 2,.6-diisopropylphenyl substituents on their nitrogen atoms were prepared from the corresponding N-heterocyclic carbenes (NHCs) by reaction with carbon dioxide. They were characterized by IR and NMR spectroscopies, and by TGA. Their ability to act as NHC precursors for in situ catalytic applications was probed in ruthenium-promoted olefin metathesis and cyclopropanation reactions. When visible light induced ring-opening metathesis polymerization of cyclooctene or cyclopropanation of styrene with ethyl diazoacetate were carried out at 60 degrees C in the presence of [RuCl2(p-cymene)](2), the NHC (.) CO2 adducts and their NHC (.) HX counterparts (X = Cl, BF4) displayed similar activities. When metathesis polymerizations were performed at room temperature, the carboxylates proved far superior to the corresponding imidazol(in)ium acid salts. They displayed the same level of activity as the preformed RuCl2(p-cymene)(IMes) complex, whereas the combination of NHC (.) HX and KO-t-Bu were almost totally inactive. Results obtained for cyclopropanation reactions at room temperature did not show such a large discrepancy of behavior between the two types of adducts. (c) 2006 Elsevier B.V. All rights reserved. [less ▲] Detailed reference viewed: 29 (0 ULg)Imidazol(in)ium carboxylates as N-heterocyclic carbene ligand precursors for Suzuki-Miyaura reactions; Delaude, Lionel ; et alin Tetrahedron Letters (2006), 47(48), 8529-8533 Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2 ... [more ▼] Simple catalysts formed in situ from palladium acetate and a variety of imidazolium and imidazolinium carboxylates and dithiocarboxylates have been screened in the coupling of aryl halides with trans-2-phenylvinylboronic acid. Imidazol(in)ium carboxylates show an excellent activity, which compares to that displayed by the parent imidazol(in)ium chlorides, whereas imidazol(in)ium dithiocarboxylates are poorly efficient. Interestingly, the base employed exerts a profound influence on the trans/cis stereochemistry of the coupling product. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲] Detailed reference viewed: 30 (1 ULg)Catalytic activity of N-heterocyclic carbene complexes of ruthenium and palladium in C-C bond forming reactionsDemonceau, Albert ; Delaude, Lionel ; et alConference (2005, August) Detailed reference viewed: 4 (1 ULg)Catalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing substituentsSauvage, Xavier ; ; et alPoster (2005) Detailed reference viewed: 20 (2 ULg)Catalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing substituentsSauvage, Xavier ; ; et alConference (2005) Detailed reference viewed: 11 (1 ULg)Catalytic applications of transition metal N-heterocyclic carbene complexes bearing nitrogen-containing side-groups; ; 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 ▲] Detailed reference viewed: 6 (0 ULg)New ruthenium catalysts bearing N-heterocyclic carbene ligands in Kharasch chemistry; ; Richel, Aurore et alPoster (2003) Detailed reference viewed: 5 (1 ULg)New ruthenium catalysts bearing N-heterocyclic carbene ligands for ATRP; ; Richel, Aurore et alin e-polymers (2003) New ruthenium catalysts bearing N-heterocyclic carbene ligands in Kharasch chemistry Detailed reference viewed: 5 (3 ULg)Tuning of ruthenium N-heterocyclic carbene catalysts for olefin polymerisation and fine chemistryDemonceau, Albert ; ; Richel, Aurore et alScientific conference (2003) Detailed reference viewed: 4 (0 ULg) |
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