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Heck-Type Reaction (heck-type + reaction)

Distribution by Scientific Domains
Chemistry83%

Selected Abstracts

Synthesis of Rhodium Colloidal Nano-Coating Grafted Mesoporous Silica Composite and its Application as Efficient Environmentally Benign Catalyst for Heck-Type Reaction of Arylboronic Acids

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2008
Liang Li
Abstract The synthesis and characterization of rhodium colloidal layer grafted mesoporous SBA-15 material, designated as SBA-Rh, are presented. In the preparation of this new catalyst, SBA-15 mesoporous material was used as support without any pretreatment. The SiH functional groups were introduced onto the surface which resulted in highly dispersed metal colloid layer both on the outer and inner surface of the supporting material. The material was investigated for Heck-type coupling reactions of alkenes with ayboronic in organic/water solvent. The ultrahigh specific area, large pore opening, and highly dispersed catalyst species in SBA-Rh material created one of the most active heterogeneous catalysts for such reactions. Rhodium element was not detected in the final mixture by ICP after reaction. The catalyst species showed very high stability against leaching from the matrix and can be recycled for repeated use. [source]

CuI/DABCO as a Highly Active Catalytic System for the Heck-Type Reaction.

CHEMINFORM, Issue 44 2005
Jin-Heng Li
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Iridium-Catalyzed Mizoroki,Heck-Type Reaction of Organosilicon Reagents.

CHEMINFORM, Issue 19 2003
Tooru Koike
No abstract is available for this article. [source]

Palladium-Catalyzed Desulfitative Mizoroki,Heck Couplings of Sulfonyl Chlorides with Mono- and Disubstituted Olefins: Rhodium-Catalyzed Desulfitative Heck-Type Reactions under Phosphine- and Base-Free Conditions.

CHEMINFORM, Issue 14 2006
Srinivas Reddy Dubbaka
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Palladium-Catalyzed Desulfitative Mizoroki,Heck Couplings of Sulfonyl Chlorides with Mono- and Disubstituted Olefins: Rhodium-Catalyzed Desulfitative Heck-Type Reactions under Phosphine- and Base-Free Conditions

CHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2005
Srinivas Reddy Dubbaka
Abstract New conditions have been found for the desulfitative Mizoroki,Heck arylation and trifluoromethylation of mono- and disubustituted olefins with arenesulfonyl and trifluoromethanesulfonyl chlorides. Thus (E)-1,2-disubstituted alkenes with high stereoselectivity and 1,1,2-disubstituted alkenes with 12:1 to 21:1 E/Z steroselectivity can be obtained. Herrmann's palladacycle at 0.1 mol,% is sufficient to catalyze these reactions, for which electron-rich or electron-poor sulfonyl chlorides and alkenes are suitable. If phosphine- and base-free conditions are required, 1 mol,% [RhCl(C2H4)2] catalyzes the desulfitative cross-coupling reactions. Contrary to results reported for [RuCl2(PPh3)2]-catalyzed coupling reactions with sulfonyl chlorides, the palladium and rhodium desulfitative Mizoroki,Heck coupling reactions are not inhibited by radical scavenging agents. Possible sulfones arising from the sulfonylation of alkenes at 60,°C are not desulfitated at higher temperatures in the presence of the Pd or Rh catalysts. De nouvelles conditions sont rapporteés pour les couplages désulfitants du type Mizoroki,Heck des chlorures d'arènesulfonyles et trifluorométhanesulfonyle avec des oléfines mono- et disubstitueés. La méthode permet la synthèse de (E)-alcènes 1,2-disubstitués avec haute stéréosélectivité et d'alkènes 1,1,2-trisubstitués avec des stéréosélectivités E/Z variant de 12:1 à 21:1. La palladacycle de Herrmann à 0.1 mol% est suffisant pour catalyser ces reactions qui peuvent engager des chlorures de sulfonyles et des alcènes soit riches ou pauvres en électron. Si des conditions sans phosphine et sans base sont requises, 1 mol,% de [RhCl(C2H4)2] est un excellent catalyseur pour ces couplages désulfitants. Contrairement à ce qui est rapporté pour des réactions analogues catalysées par [RuCl2(PPh3)2] et qui impliquent des intermédiaires radicalaires, les couplages du type Mizoroki,Heck désulfitants catalysés par des complexes de palladium ou de rhodium ne sont pas inhibés par des pièges à radicaux. De plus, les sulfones qui peuvent se former par sulfonylation des alcènes (60,oC) ne sont pas désulfitées à plus haute température en présence des catalyseurs au Pd ou au Rh. [source]

Rapid Screening of New Polymer-Supported Palladium (II) Bis(3,4,5,6-tetrahydropyrimidin-2-ylidenes),

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2004
Monika Mayr
Abstract Summary: The synthesis of two 1,3-diaryl-3,4,5,6-tetrahydropyrimidin-2-ylidene-based N -heterocyclic carbene- (NHC) derived palladium complexes, Pd(5-hydroxy-1,3-bis-(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (Ag2Br2Cl4) (10) and Pd(5-(bicyclo[2.2.1]hept-5-ene-2-carbonyloxy)-1,3-bis-(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene) (Ag2Br2Cl4) (11) is described. 10 was supported on a PS-DVB and a Wang resin, respectively, to yield catalysts 12 and 13, while 11 was used for the synthesis of a ring-opening metathesis precipitation polymerization-derived support 14. All supports were tested for their activity in Heck-type reactions using a combinatorial approach. Structure of polymer supported Pd-catalysts. [source]