Palladium-Catalyzed Oxidative Carbonylation of Benzylic C–H Bonds via Nondirected C(sp<sup>3</sup>)–H Activation

Xie, Pan; Xie, Yinjun; Qian, Bo; Zhou, Han; Xia, Chungu; Huang, Hanmin

doi:10.1021/ja3036459

Cited by 260 publications

(68 citation statements)

References 56 publications

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“…Typical aminocarbonylations catalysed by Pd usually start from the corresponding iodides or bromides, and require high CO pressures and high reaction temperatures. Obviously, further efforts in our systems have to be directed to the transformation of the stoichiometric process into a catalytic one, a challenge that is still not accomplished in the case of the aminocarbonylation, even though several catalytic examples are known of the related alkoxycarbonylation reaction [25–30]. …”

Section: Resultsmentioning

confidence: 99%

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

Urriolabeitia

Laga²,

Cativiela³

2012

Beilstein J. Org. Chem.

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SummaryA new method for the regioselective synthesis of 2-alkoxycarbonyl- and 2-(aminocarbonyl)phenylglycinate methyl esters has been developed. The reaction of the orthopalladated complex [Pd(μ-Cl)(C6H4(CH(CO2Me)NMe2)-2)]2 (1) with nucleophiles HNu under a CO atmosphere results in the selective incorporation of the C(O)Nu moiety to the phenyl ring and formation of the carbonyl species ortho-C6H4(C(O)Nu)(CH(CO2Me)NMe2) (2a–j) (Nu = OR, NHR, NR2). Compounds 2a–j are conformationally restricted analogues of glutamic acid and glutamine and are interesting due to their biological and pharmacological properties. The reaction of [Pd(μ-Cl)(C6H4(CH(CO2Me)NHTf)-2)]2 (3) with nucleophiles in a CO atmosphere results, however, in the formation of the cyclic isoindolinone or the open 2-carboxyphenylglycine methyl esters, with the reaction outcome being driven by the choice of the solvent.

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Section: Resultsmentioning

confidence: 99%

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

Urriolabeitia

Laga²,

Cativiela³

2012

Beilstein J. Org. Chem.

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“…Further improving atom economy, alkyl radicals were also generated from benzylic C−H bonds by alkoxyl radicals through intermolecular H atom abstraction. By using this strategy, the group of Huang prepared various 2‐arylacetic acid esters from the corresponding alkyl arenes, CO, and alcohols …”

Section: Radical–metal Crossover Reactionsmentioning

confidence: 99%

The Persistent Radical Effect in Organic Synthesis

2019

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Radical–radical couplings are mostly nearly diffusion‐controlled processes. Therefore, the selective cross‐coupling of two different radicals is challenging and not a synthetically valuable transformation. However, if the radicals have different lifetimes and if they are generated at equal rates, cross‐coupling will become the dominant process. This high cross‐selectivity is based on a kinetic phenomenon called the persistent radical effect (PRE). In this Review, an explanation of the PRE supported by simulations of simple model systems is provided. Radical stabilities are discussed within the context of their lifetimes, and various examples of PRE‐mediated radical–radical couplings in synthesis are summarized. It is shown that the PRE is not restricted to the coupling of a persistent with a transient radical. If one coupling partner is longer‐lived than the other transient radical, the PRE operates and high cross‐selectivity is achieved. This important point expands the scope of PRE‐mediated radical chemistry. The Review is divided into two parts, namely 1) the coupling of persistent or longer‐lived organic radicals and 2) “radical–metal crossover reactions”; here, metal‐centered radical species and more generally longer‐lived transition‐metal complexes that are able to react with radicals are discussed—a field that has flourished recently.

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“…Die Atomökonomie wurde weiter verbessert, indem die Alkyl‐Radikale aus benzylischen C‐H‐Bindungen mit Alkoxyl‐Radikalen mittels einer intermolekularen H‐Atom‐Abstraktion erzeugt wurden. Mit dieser Strategie stellte die Gruppe von Huang erfolgreich verschiedene 2‐Arylessigsäureester ausgehend von den entsprechenden Alkylarenen, CO und Alkoholen her …”

Section: Radikal‐metall‐kreuzungsreaktionenunclassified

Der “Persistent Radical Effect” in der organischen Chemie

2019

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Radikal‐Radikal‐Kupplungen sind nahezu diffusionskontrollierte Prozesse. Daher sind selektive Kreuzkupplungen zweier unterschiedlicher Radikale schwierig zu realisieren und stellen somit synthetisch nicht wertvolle Prozesse dar. Wenn die beiden Radikale allerdings eine unterschiedliche Lebensdauer aufweisen und in gleichen Raten gebildet werden, wird die Kreuzkupplung zum dominierenden Prozess. Die hohe Kreuzselektivität basiert auf einem kinetischen Phänomen, dem “Persistent Radical Effect” (PRE). In diesem Aufsatz wird eine von Simulationen einfacher Modellsysteme gestützte Erklärung des PRE geliefert. Weiter werden die Stabilität von Radikalen in Bezug auf ihre Lebensdauer und verschiedene Beispiele für PRE‐vermittelte Radikal‐Radikal‐Kupplungen in der Synthese diskutiert. Es wird gezeigt, dass der PRE nicht auf Kupplungen persistenter mit transienten Radikalen beschränkt ist. Der PRE mit einhergehender hoher Kreuzselektivität greift bereits, wenn ein Kupplungspartner langlebiger als das andere transiente Radikal ist. Diese Tatsache erweitert signifikant das Anwendungsgebiet PRE‐vermittelter Radikalchemie. Dieser Aufsatz ist in zwei Teile aufgeteilt: 1) die Kupplung persistenter oder langlebiger organischer Radikale und 2) Radikal‐Metall‐Kreuzungsreaktionen; hierbei werden Metall‐zentrierte Radikalspezies oder allgemeiner langlebige Übergangsmetallkomplexe, welche mit Radikalen reagieren, diskutiert – ein Gebiet, das jüngst stark expandiert ist.

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Palladium-Catalyzed Oxidative Carbonylation of Benzylic C–H Bonds via Nondirected C(sp³)–H Activation

Cited by 260 publications

References 56 publications

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

The Persistent Radical Effect in Organic Synthesis

Der “Persistent Radical Effect” in der organischen Chemie

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Palladium-Catalyzed Oxidative Carbonylation of Benzylic C–H Bonds via Nondirected C(sp3)–H Activation

Cited by 260 publications

References 56 publications

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

Synthesis of conformationally restricted glutamate and glutamine derivatives from carbonylation of orthopalladated phenylglycine derivatives

The Persistent Radical Effect in Organic Synthesis

Der “Persistent Radical Effect” in der organischen Chemie

Contact Info

Product

Resources

About

Palladium-Catalyzed Oxidative Carbonylation of Benzylic C–H Bonds via Nondirected C(sp³)–H Activation