Ligand‐Promoted Palladium‐Catalyzed C−H Acetoxylation of Simple Arenes

Valderas, Carolina; Naksomboon, Kananat; Fernández-Ibáñez, M. Á́ngeles

doi:10.1002/cctc.201600757

Cited by 28 publications

(21 citation statements)

References 51 publications

(15 reference statements)

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“…Homogeneous Pd II catalysts are active in both ligand-directed [3,[75][76][77] and non-directedC ÀHb ond acetoxylation, [4,10,[78][79][80] mainly using Pd(OAc) 2 as ac atalyst, pyridines as ancillary ligands,and PhI(OAc) 2 as an oxidant. As ab enchmark for the activity and selectivity of our palladium-containing polymers we chose the non-directed CÀHa cetoxylation of arenes, and for the optimization of reactionc onditions we used biphenyl as the substrate, so that there would also be as electivity issue.…”

Section: Activityinc àHa Ctivationmentioning

confidence: 99%

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Majeed

Shayesteh

Wallenberg

et al. 2017

Chemistry A European J

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Heterogeneous catalysts for selective oxidation of C-H bonds were synthesized by co-polymerization of new N-heterocyclic carbene-palladium(II) (NHC-Pd ) monomers with divinylbenzene. The polymer-supported NHC-Pd -catalysed undirected C-H acetoxylation of simple and methylated arenes as well as polyarenes, with similar or superior efficiency compared to their homogeneous analogues. In particular, the regioselectivity has been improved in the acetoxylation of biphenyl and naphthalene compared to the best homogeneous catalysts. The new polymer-supported catalysts maintain the original oxidation state of Pd after repeated catalytic reactions, and exhibit no significant leaching of palladium. In addition, the new catalysts have been successfully recovered and reused without loss of activity over several cycles of reactions.

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Section: Activityinc àHa Ctivationmentioning

confidence: 99%

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

Majeed

Shayesteh

Wallenberg

et al. 2017

Chemistry A European J

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“…Even more significant increases were observed with quinoline/pyridine-carboxylate ligands L7-L9 . 19 In particular, the use of 5 mol % of 2-picolinic acid ( L8 ) or of 2-quinaldic acid ( L9 ) resulted in an approximately 80% yield of 1a (entries 9 and 12). With picolinic acid, the reaction was sensitive to the ligand loading, and the yield of 1a dropped to 24% upon the addition of 20 mol % of L8 (entry 11).…”

Section: Resultsmentioning

confidence: 99%

Second-Generation Palladium Catalyst System for Transannular C–H Functionalization of Azabicycloalkanes

2018

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This Article describes the development of a second-generation catalyst system for the transannular C–H functionalization of alicyclic amines. Pyridine- and quinoline-carboxylate ligands are shown to be highly effective for increasing the reaction rate, yield, and scope of Pd-catalyzed transannular C–H arylation reactions of azabicyclo[3.1.0]hexane, azabicyclo[3.1.1]heptane, azabicyclo[3.2.1]octane, and piperidine derivatives. Mechanistic studies reveal that the pyridine/quinoline-carboxylates play a role in impeding both reversible and irreversible catalyst decomposition pathways. These ligands enable the first reported examples of the transannular C–H arylation of the ubiquitous tropane, 7-azanorbornane, and homotropane cores. Finally, the pyridine/quinoline-carboxylates are shown to promote both transannular C–H arylation and transannular C–H dehydrogenation on a homotropane substrate.

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“…[44] Ein Verhältnis von 0.9:1 von Pyridin zu Palladium ist entscheidend, um zuvor schwer zu aktivierende elektronenarme Substrate mit hoher Ausbeute umzusetzen. [46] Trotz dieser Fortschritte sind die diskutierten Methoden immer noch durch die Notwendigkeit, mindestens 10 ¾quivalente des Arens einzusetzen, beschränkt. Durch die Verwendung von MesI(OAc) 2 als Oxidationsmittel konnte die Regioselektivitätf ür1 ,2-Dichlorbenzol auf a/b = 11:89 verbessert werden.…”

Section: Oxygenierungunclassified

“…[44,45] In einer aktuellen Studie erweiterten Fernµndez-IbµÇez und Mitarbeiter das Substratspektrum über die Verwendung von 6-Fluorpicolinsäure als Liganden um eine Reihe elektronisch unterschiedlicher Aromaten. [46] Trotz dieser Fortschritte sind die diskutierten Methoden immer noch durch die Notwendigkeit, mindestens 10 ¾quivalente des Arens einzusetzen, beschränkt.…”

Section: Aminierungunclassified