Microwave‐Assisted Palladium‐Catalyzed Heterogeneous Vinylation of 2(1<i>H</i>)‐Pyridones

Singh, Brajendra K.; Cavalluzzo, Claudia; Maeyer, Marc De; Debyser, Zeger; Parmar, Virinder S.; Eycken, Erik V. Van der

doi:10.1002/ejoc.200900677

Cited by 13 publications

(9 citation statements)

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“…Regardless of the time employed, (Entries 30-32, Table 9). The strongly activated ring is believed to account for this outcome, as has been noted in the literature 12,14,20,21. It should be noted here for the reader that although our methodology was unproductive, Fu and Nolan’s pre-mentioned vinylation methods appear to be a more amenable to substrates involving extremely electron rich and sterically hindered aryl halides 5,6…”

supporting

confidence: 57%

Studies of microwave-enhanced Suzuki–Miyaura vinylation of electron-rich sterically hindered substrates utilizing potassium vinyltrifluoroborate

Brooker

Cooper

Hodges

et al. 2010

Tetrahedron Letters

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The Suzuki-Miyaura cross-coupling of sterically hindered and electron-rich ortho,ortho'-substituted aryl halides with potassium vinyltrifluoroborate utilizing microwave irradiation has been conducted while adjusting solvent ratio, irradiation time, and catalyst loading to find optimal conditions. Coupling of benzyl 3,5-bis(benzyloxy)-4-bromobenzoate leads to a mixture of the desired styrene derivative, and the reduced product. 4-Bromo-1,3,5-trimethoxybenzene, methyl 4-bromo-3,5-dimethoxybenzoate, and mesitylene bromide were also coupled to test the breadth and scope of this methodology. Of these substrates tested only 4-bromo-1,3,5-trimethoxybenzene was not vinylated successfully, which is believed to be due to the electron rich nature of this system. KeywordsSuzuki-Miyaura; Potassium vinyltrifluoroborate; Styrenes; Palladium catalysis; Hindered aryl bromides Substituted styrenes (typically assembled using a transition metal-mediated cross-coupling) are useful intermediates in both the formation of new polymeric material and in the formation of specialty chemicals. 1 Mild vinylation of aryl bromides and/or iodides using trivinylcyclotriboroxane,1 vinylmagnesium bromide,2 vinyltrimethylsilane,3 and vinylpolysiloxanes 4 has been observed. N-Heterocyclic carbenes bearing palladium (II) catalysts have demonstrated high catalytic activity capable of coupling unactivated aryl chlorides. 5 Aryl bromides and activated aryl chlorides also undergo mild palladiumcatalyzed couplings at room temperature with alkenes utilizing dicyclohexylmethylamine as © 2010 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: 843-953-6587; fax 843-953-1404; wyattj@cofc.edu.Publisher's Disclaimer: 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 citable 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. (2) with the assistance of microwave irradiation. NIH Public AccessScheme 1 illustrates the first reaction of interest, and the two possible products of the crosscoupling reaction; the desired vinylated product, benzyl 3,5-bis(benzyloxy)-4-vinylbenzoate (3), and reduced product, benzyl 3,5-bis(benzyloxy)benzoate (4). As with conventional conditions 14 the reduced product was observed under microwave conditions, but only in trace amounts (less than 1% of the total product distribution). Product ratios were determined, if necessary, using 1 H NMR integration of the crude reaction mixture using the methylene hydrogens from the benzyl ethers of the starting material 1, as well as for the vinyl product 3; chemical shifts of 5.18 ppm (s, 4H) and 5.14 ppm (s, 4H), respectively. The amount of reduced product 4, if any, was determined by integration of the triplet at 6...

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supporting

confidence: 57%

Studies of microwave-enhanced Suzuki–Miyaura vinylation of electron-rich sterically hindered substrates utilizing potassium vinyltrifluoroborate

Brooker

Cooper

Hodges

et al. 2010

Tetrahedron Letters

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“…[135] Several reports of cross-coupling approaches to afford 4-(or 5-)alkenyl 2-pyrones (or 2-pyridones) have been published. The majority of examples employ a halogenated 2pyrone (2-pyridone) and Mizoroki-Heck, [136] Suzuki-Miyaura, [137] Stille, [138] as well as Negishi reactions are known. As reported by Itahara and Ouseto in 1984 (Scheme 29), [139] N-methyl-2-pyridone (177) was converted into the corresponding 4-alkenyl analogue 178 in an example of CÀH activation that pre-dates the current interest in this transformation by over 20 years.…”

Section: Angewandte Chemiementioning

confidence: 99%

Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

2012

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Twenty-seven years ago, H. Hopf published the only previous comprehensive review on branched oligoenes that had the title "Dendralenes: A Neglected Family of Hydrocarbons". The dendralenes are no longer neglected. Research into the synthesis, properties, and applications of dendralenes is rapidly gaining momentum and this Review summarizes important recent findings. From significant fundamental properties (the first demonstration of alternating behavior since the annulenes) through to unparalleled complexity-generating synthetic transformations, this fundamental oligoene family is coming of age. Effective synthetic approaches to cyclic and acyclic dendralene systems are analyzed and classified. The most powerful synthetic transformations of the dendralenes, diene-transmissive Diels-Alder reactions, are surveyed in detail.

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“…[135] Mehrere Arbeiten berichten über Kreuzkupplungsrouten zu 4(oder 5)-Alkenyl-2-pyronen (oder -2-pyridonen). Die Mehrzahl der Beispiele verwendet ein halogeniertes 2-Pyron (2-Pyridon), und Mizoroki-Heck-, [136] Suzuki-Miyaura-, [137] Stille- [138] sowie Negishi-Reaktionen sind bekannt. Wie 1984 von Itahara und Ouseto berichtet (Schema 29), [139] wurde N-Methyl-2-pyridon (177) [142] Wir mçchten auch auf einen interessanten und allgemeinen -zumindestens hinsichtlich der Ringgrçße -Zugang zu 1,3-Cyclo [ [144] Ferner wurde über andere vereinzelte Beispiele zu Transformationen vom Eninmetathesetyp berichtet.…”

Section: Cyclische Dendralenderivateunclassified

Dendralene auf dem Vormarsch: kreuzkonjugierte Oligoene ermöglichen den schnellen Aufbau molekularer Komplexität

Hopf

Sherburn

2012

Angewandte Chemie

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Vor 27 Jahren veröffentlichte H. Hopf den bisher einzigen umfassenden Übersichtsartikel zu verzweigten Oligoenen mit dem Titel “Dendralene – eine vernachlässigte Gruppe hochungesättigter Kohlenwasserstoffe”. Die Dendralene werden heutzutage nicht mehr vernachlässigt. Die Forschung zu Synthese, Eigenschaften und Anwendungen der Dendralene hat in jüngster Zeit viele neue Impulse erhalten, und der vorliegende Aufsatz fasst die bedeutenden Ergebnisse der letzten Jahre zusammen. Von grundlegend wichtigen Eigenschaften (der ersten Demonstration von alternierendem Verhalten seit den Annulenen) bis zu unvergleichbaren, molekulare Komplexität erzeugenden, chemischen Transformationen: Die als Dendralene bekannte Klasse der Oligoene ist erwachsen geworden! Die verschiedenen Synthesewege zu acyclischen und cyclischen Dendralenen werden analysiert und klassifiziert. Die leistungsfähigste Umwandlung der Dendralene – die Dien‐transmissive Diels‐Alder‐Reaktion (DTDA‐Reaktion) – wird in einer detaillierten Übersicht vorgestellt.

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Microwave‐Assisted Palladium‐Catalyzed Heterogeneous Vinylation of 2(1H)‐Pyridones

Cited by 13 publications

References 43 publications

Studies of microwave-enhanced Suzuki–Miyaura vinylation of electron-rich sterically hindered substrates utilizing potassium vinyltrifluoroborate

Studies of microwave-enhanced Suzuki–Miyaura vinylation of electron-rich sterically hindered substrates utilizing potassium vinyltrifluoroborate

Dendralenes Branch Out: Cross‐Conjugated Oligoenes Allow the Rapid Generation of Molecular Complexity

Dendralene auf dem Vormarsch: kreuzkonjugierte Oligoene ermöglichen den schnellen Aufbau molekularer Komplexität

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