Acetylene-bridged P,C,P′-ligands and corresponding cyclopalladated compounds

“…[9] Procedures involving nitration followed by hydrogenation are not tolerated by many functional groups and are often complicated due to the need for protection and deprotection steps. The direct nucleophilic substitution of aryl halides is a synthetic route dedicated only to substrates that contain electron-withdrawing groups, including perfluorinated compounds, [10,11] and Ullmann-type substitution reactions occur at high temperatures, giving generally diarylation products, and depend strongly on the nature of the substrate substituents. [12] These drawbacks are limiting factors for the synthesis of aryl-substituted polyamines, especially nonsymmetrical derivatives, as multistep syntheses are often required to prepare even simple species.…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Arylation of Linear and Cyclic Polyamines

et al. 2005

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Synthetic protocols for the palladium-catalyzed arylation of various linear and cyclic polyamines and polyoxapolyamines has been worked out. Pd(0) and Pd(II) complexes with such phosphine ligands as dppf, BINAP, PPF-OMe, P(tBu) 3 , 2-ditert-butylphosphino-1,1′-biphenyl have been explored in the catalytic amination reactions. Monoamination of chloro-, bromo-, and iodoarenes with di-, tri-, and tetraamines have been carried out, conditions for di-and polyarylation of linear polyamines have been elaborated. Successful arylation of 1,4,7,10-tetraazacyclododecane (cyclene) and 1,4,8,11-tetraazacyclotetradecane (cyclam) have been conducted. Intramolecular diamination of dihaloarenes such as 1,2-dibromobenzene, 2,6-dichlorobromobenzene, 1,3-dibromobenzene, 1,8-dichloroanthracene, 1,8-dichloroanthraquinone, 1,5-dichloroanthracene, and 1,5-dichloroanthraquinone afforded corresponding polyazamacrocycles containing arene moieties. For the first time, a convenient one-pot synthesis of the face-to-face arranged bismacrocyclic systems has been carried out.

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“…Palladacyclic catalyst precursors for the Heck reaction It was recently demonstrated that cationic derivatives of binuclear conjugated palladacycles (Scheme 5) are also highly active catalyst precursors for the Heck reaction of iodobenzene with styrene or methyl acrylate. [31] Palladacycles can also be involved in recyclable catalytic systems, e.g. by running the reaction of phosphapalladacycle 1 [32,33] in ionic liquids, [34] or by employing the polyethylene glycol bound sulfur-containing palladacycle 9 [28] or the polystyrene-bound imine-containing palladacycle (see later).…”

Section: Scheme 3 Heck Coupling Reactionmentioning

confidence: 99%

Palladacycles − An Old Organometallic Family Revisited: New, Simple, and Efficient Catalyst Precursors for Homogeneous Catalysis

Dupont

Pfeffer

Spencer

2001

Eur. J. Inorg. Chem.

425

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Nitrogen-, phosphorus-, and sulfur-containing palladacycles, typically containing four-or six-electron donor anionic metallated ligands, are emerging as a new family of organometallic catalyst precursors. These thermally and air-stable complexes are easy to handle and their synthesis is often [a] interface of inorganic, organometallic, and organic chemistry, with an emphasis on metal-mediated functionalization of CϪH bonds through reactions aimed at producing new carbonϪcarbon or carbonϪheteroatom bonds. John Spencer obtained a B.Sc. (1st class, Hon.) at Sussex University in Chemistry with European Studies in 1990 before studying for a Ph.D. under the supervision of Michel Pfeffer, Strasbourg (1990Ϫ1994). After a postdoctoral stay with Antonio Togni at the ETH, Zurich, he returned to England where he first worked in the pharmaceutical industry (Xenova, Cerebrus) . He then took up his current position at the Thrombosis Research Institute (London), where he is now a Senior Research Scientist. He is a co-author of over a dozen papers and patents and his research interests include organopalladium and organoboron chemistry, as well as asymmetric catalysis.MICROREVIEWS: This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included.1917 straightforward. Palladacycles are now being successfully exploited in catalytic reactions ranging from classical hydrogenations to enantioselective aldol-type condensations. The main recent achievements pertaining to their use in homogeneous organometallic catalysis are outlined herein.

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Acetylene-bridged P,C,P′-ligands and corresponding cyclopalladated compounds

Abstract: Bis-'pincer'-cyclopalladates 1 and 2 containing an ethynediyl-or a butadiynediyl-bridge have been synthesized, characterized and used as precatalysts in the Heck reaction.

Cited by 46 publications

References 4 publications

Palladacycles in catalysis – a critical survey

Palladacycles in catalysis – a critical survey

Palladium‐Catalyzed Arylation of Linear and Cyclic Polyamines

Palladacycles − An Old Organometallic Family Revisited: New, Simple, and Efficient Catalyst Precursors for Homogeneous Catalysis

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