Palladium/polystyrene catalysts

Bergbreiter, David E.; Chen, Bushi; Lynch, Thomas J.

doi:10.1021/jo00171a005

Cited by 50 publications

(12 citation statements)

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“…The reaction was monitored by a hydrogen uptake at different intervals of time. 22 The products obtained were identified using HPLC, IR spectra and GC-MS. 23 A blank reaction was also carried out for all the substrates without using the catalyst.…”

Section: Methodsmentioning

confidence: 99%

Synthesis, Characterisation of Polymer-Supported Palladium-2-Methylimidazole Complex Catalyst for the Hydrogenation of Aromatic Nitro Compounds

Velua¹,

Alexander

Gayathri

et al. 2011

Journal of Chemical Research

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A polymer-supported palladium-2-methylimidazole complex was synthesised and characterised by various physicochemical methods. The complex was successfully used as a catalyst for the hydrogenation of nitrobenzene and a few of its derivatives under ambient conditions. Results reveal that the electronic as well as the steric effects of the substitutent control the rate of hydrogenation of the nitro group in the studied nitro compounds. The kinetics of hydrogenation and the reusability of the catalyst were also studied.

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Section: Methodsmentioning

confidence: 99%

Synthesis, Characterisation of Polymer-Supported Palladium-2-Methylimidazole Complex Catalyst for the Hydrogenation of Aromatic Nitro Compounds

Velua¹,

Alexander

Gayathri

et al. 2011

Journal of Chemical Research

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“…Furthermore, Bergbreiter et al obtained only a 5 % yield for the allylation of piperidine with allyl alcohol in the presence of a heterogeneous polystyrene-bound palladium catalyst at 100°C under neat conditions. [28] On modifying Atkins' conditions (i.e., using a different catalytic system and a solvent), Mortreux et al obtained no more than a 46 % yield in the allylation of diethylamine [Equation (7)]. [27] Nevertheless, the allylation of diethylamine occurs effectively in the presence either of Pd-(OAc) 2 /diphosphane (dppe or dppb) in propylene glycol [29,30] or of Pd(OAc) 2 /TPPTS in aqueous pentane at 110°C.…”

Section: -Catalyzed Allylations In the Absence Of Activatormentioning

confidence: 99%

Procedures for and Possible Mechanisms of Pd‐Catalyzed Allylations of Primary and Secondary Amines with Allylic Alcohols

Мuzart

2007

Eur J Org Chem

166

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This review describes the different Pd‐catalyzed methods that afford allylic amines from intermolecular reactions between allylic alcohols and amines and, with personal comments, the mechanisms that have been proposed. Allylic amines are an important class of compounds, while a wide structural variety of allylic alcohols are commercially available and are abundant in nature. The advantages of the use of allylic alcohols over that of their derivatives such as allylic esters or carbonates are the high atom efficiency and the formation only of water as the by‐product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

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“…Some years ago we had noted that classical Pd-C catalysts, under relatively mild conditions (i.e., at reaction temperatures <100°C) (3,4), exhibit reactivity resembling that of the well-established homogeneous Pd catalyst, tetrakis(triphenylphosphine)palladium(0). Specifically, we found that both a supported Pd(0) species prepared from an organometallic derivative of cross-linked polystyrene (5) and simple Pd-C could effectively catalyze allylic substitution of allyl acetates by nucleophiles like secondary amines. In these cases, catalysis was most effective in the presence of a soluble phosphine with reactions sometimes occurring at room temperature.…”

Section: Introductionmentioning

confidence: 99%

Catalysis with palladium colloids supported in poly(acrylic acid)-grafted polyethylene and polystyrene

Bergbreiter¹,

Kippenberger²,

Zhong³

2006

Can. J. Chem.

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Grafts of poly(acrylic acid) on polyethylene powder (PE-g-PAA) or polystyrene (PS-g-PAA) can be used to support Pd(0) crystallites that function like a homogeneous Pd(0) catalyst in some reactions. These Pd-PE-g-PAA catalysts were active in allylic substitution reactions in the presence of added phosphine ligand. A catalyst analogous to the Pd-PE-g-PAA powder catalyst on polystyrene (Pd-PS-g-PAA) was similarly active for allylic substitution and could also be used in Heck reactions at 80-100°C in N,N-dimethylacetamide (DMA). Analysis of the product solutions for Pd leachate and a correlation of the Pd leaching with product formation in the allylic substitution chemistry for both types of catalysts suggests that the active catalysts in these reactions are leached from the support. In the case of the allylic substitution reaction, external triphenylphosphine and substrate together are required for the chemistry and Pd leaching.Résumé : Les produits de greffage d'acide polyacrylique sur de la poudre de polyéthylène (PE-g-APA) ou de polystyrène (PS-g-APA) peuvent être utilizés comme support de cristallites de Pd(0) qui, dans certaines réactions, peuvent fonctionner comme catalyseur de Pd(0). Ces catalyseurs de Pd-PE-g-APA mis en présence d'un ligand phosphine sont actifs dans les réactions de substitution allylique. Un catalyseur analogue au catalyseur en poudre Pd-PE-g-APA sur du polystyrène (Pd-PS-g-APA) est aussi actif pour la réaction de substitution allylique et il peut aussi être utilizé dans les réactions de Heck, à des températures allant de 80 à 100°C, dans le N,N-diméthylacétamide (DMA). Une analyse des solutions de produits pour rechercher la présence de Pd qui aurait été lessivé ainsi qu'une corrélation du Pd de lessivage avec la formation de produit dans la chimie de la substitution allylique pour les deux types de catalyseur suggère que les catalyseurs actifs dans ces réactions sont lessivés de leur support. Dans le cas de la réaction de substitution allylique, la présence simultanée de la triphénylphosphine externe et du substrat sont requis pour la chimie et le lessivage du Pd.

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Palladium/polystyrene catalysts

Cited by 50 publications

References 0 publications

Synthesis, Characterisation of Polymer-Supported Palladium-2-Methylimidazole Complex Catalyst for the Hydrogenation of Aromatic Nitro Compounds

Synthesis, Characterisation of Polymer-Supported Palladium-2-Methylimidazole Complex Catalyst for the Hydrogenation of Aromatic Nitro Compounds

Procedures for and Possible Mechanisms of Pd‐Catalyzed Allylations of Primary and Secondary Amines with Allylic Alcohols

Catalysis with palladium colloids supported in poly(acrylic acid)-grafted polyethylene and polystyrene

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