An Industrially Viable Catalyst System for Palladium‐Catalyzed Telomerizations of 1,3‐Butadiene with Alcohols

Jackstell, Ralf; Harkal, Surendra; Jiao, Haijun; Spannenberg, Anke; Borgmann, Cornelia; Röttger, Dirk; Nierlich, F.; Elliot, M. S.; Niven, Stuart; Cavell, Kingsley J.; Navarro, Oscar; Viciu, Mihai S.; Nolan, Steven P.; Beller, Matthias

doi:10.1002/chem.200400182

Cited by 131 publications

(96 citation statements)

References 66 publications

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“…Within this context, an NMR control experiment in toluene-d 8 confirmed the formation of a defined Pd-carbene complex under these conditions. [12] A cyclisation of 1 carried out with the Pd catalyst from the NMR sample gave an almost identical reaction outcome as that reported in Table 1, entry 5. In addition to the use of 3, related carbenes 4 and 5 yielded similar results (entries 9, 10).…”

supporting

confidence: 58%

Palladium‐Carbene Catalysts for Aerobic, Intramolecular Wacker‐Type Cyclisation Reactions

Muñiz¹

2004

Adv Synth Catal

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supporting

confidence: 58%

Palladium‐Carbene Catalysts for Aerobic, Intramolecular Wacker‐Type Cyclisation Reactions

Muñiz¹

2004

Adv Synth Catal

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“…In keinem Fall gelang aber der Aufbau eines Stereozentrums, und keiner der Komplexe wurde für asymmetrische Heck-Mizoroki-Reaktionen eingesetzt. [111,271,272] Unter den verschiedenen NHC-Ligandenvorstufen, die in das Screening einbezogen wurden, ergab IMes·HCl (11, Tabelle 1) die höchste TON (94 000). [271,272] [274] oder Sulfonamiden [275] …”

Section: G Organ Et Alunclassified

Aus der Sicht des Synthetikers: Palladiumkomplexe N‐heterocyclischer Carbene als Katalysatoren für Kreuzkupplungen

2007

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Palladiumkatalysierte C‐C‐ und C‐N‐Kupplungen zählen zu den vielseitigsten und leistungsfähigsten Syntheseverfahren. Seit 15 Jahren erfreuen sich die N‐heterocyclischen Carbene (NHCs) wachsender Beliebtheit als Liganden für palladiumvermittelte Kreuzkupplungen und ähnliche Methoden. Sie sind in vielerlei Hinsicht den üblichen tertiären Phosphanen überlegen. Weil NHCs stark σ‐elektronenschiebend sind, können sie auch anspruchsvolle Substrate zu oxidativen Insertionen bewegen. Andererseits führen ihre Sperrigkeit und ihre besondere Topologie zu einer raschen reduktiven Eliminierung. Schließlich tragen die starken Pd‐NHC‐Bindungen zur hohen Stabilität der aktiven Spezies bei – auch bei niedrigen Ligand/Pd‐Verhältnissen und hohen Temperaturen. Wenn erst stabile, anwenderfreundliche und leistungsstarke NHC‐Pd‐Präkatalysatoren kommerziell verfügbar sind, liegt das Ziel eines universellen Kreuzkupplungskatalysators in greifbarer Nähe. Dieser Aufsatz beschreibt zunächst die chemischen Grundlagen zu den NHC‐Pd‐Komplexen, um ihre Besonderheiten kennenzulernen. Anschließend folgt eine umfassende Diskussion zur Anwendung dieser Katalysatoren in C‐C‐ und C‐N‐Kreuzkupplungen sowie in der Carbopalladierung.

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“…Compared to the TPP ligand, the IMes-modified systems showed a distinctively lower selectivity to the byproducts 2, 3 and vinylcyclohexene 4, resulting in a higher n:iso ratio. The formation of byproducts with Pd-TPP was probably due to the higher sensitivity of the TPP system to an excess of ligand due to its lower steric demand [9]. For the TPP system, the coordination of a second ligand is facilitated leading to lower 1-Mode selectivity as reported by Vollmüller et al [10].…”

Section: Parameter Variationmentioning

confidence: 75%

“…In recent years, N-heterocyclic carbene (NHC) ligands have been used to modify the palladium catalyst [7][8][9]. Compared to the traditional phosphine-modified systems, higher chemo-and regioselectivity and significantly higher activity have been reported.…”

Section: Introductionmentioning

confidence: 99%

Pd-catalyzed telomerization of butadiene and methanol with direct catalyst recycling using a liquid-ionic liquid biphasic, continuous process

Völkl

Geburtig

Kiermaier

et al. 2016

Chemical Engineering and Processing: Process Intensification

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Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol ndash a kinetic study combined with model-based experimental analysis, Chemical Engineering and Processing http://dx.doi.org/10. 1016/j.cep.2015.07.007 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol -a kinetic study combined with model-based experimental analysis The telomerization of butadiene with methanol was investigated in the presence of different palladium catalysts modified either with triphenylphosphine (TPP) or 1,3-dimesityl-imidazol-2-ylidene (IMes) ligand. When pure butadiene was used as substrate, a moderate selectivity for the Pd-TPP catalyst toward the desired product 1-methoxy-2,7-octadiene (1-Mode) of around 87 % was obtained, while the IMes carbene ligand almost exclusively formed 1-Mode with 97.5 % selectivity. The selectivity remained unchanged when the pure butadiene feed was replaced by synthetic crack-C 4 (sCC 4 ), a technical feed of 45 mol % butadiene and 55 mol % inerts (butenes and butanes). The TPP-modified catalyst showed a lower reaction rate, which was attributed to the expected dilution effect caused by the inerts. Surprisingly, the IMes-modified catalyst showed a higher rate with sCC 4 compared to the pure feed. By means of a model-based experimental analysis, kinetic rate equations could be derived. The kinetic modeling supports the assumption that the two catalyst systems follow different kinetic rate equations. For the Pd-TPP catalyst, the reaction kinetics were related to the Jolly mechanism. In contrast, the Jolly mechanism had to be adapted for the Pd-IMes catalyst as the impact of the base seems to differ strongly from that for the Pd-TPP catalyst. The Pd-IMes system was found to be zero order in butadiene at moderate to high butadiene concentrations and first order in base while the nucleophilicity of the base is influenced by the methanol amount resulting in a negative reaction order for methanol.

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An Industrially Viable Catalyst System for Palladium‐Catalyzed Telomerizations of 1,3‐Butadiene with Alcohols

Cited by 131 publications

References 66 publications

Palladium‐Carbene Catalysts for Aerobic, Intramolecular Wacker‐Type Cyclisation Reactions

Palladium‐Carbene Catalysts for Aerobic, Intramolecular Wacker‐Type Cyclisation Reactions

Aus der Sicht des Synthetikers: Palladiumkomplexe N‐heterocyclischer Carbene als Katalysatoren für Kreuzkupplungen

Pd-catalyzed telomerization of butadiene and methanol with direct catalyst recycling using a liquid-ionic liquid biphasic, continuous process

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