Intermolecular Amidation of Unactivated sp<sup>2</sup> and sp<sup>3</sup> C−H Bonds via Palladium-Catalyzed Cascade C−H Activation/Nitrene Insertion

Thu, Hung‐Yat; Yu, Wing‐Yiu; Che, Chi‐Ming

doi:10.1021/ja062856v

Cited by 660 publications

(211 citation statements)

References 28 publications

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“…Thu, Yu,a nd Che reported ap alladium-catalyzed oximedirected CÀHa midation (Scheme 9). [26] In this approach, an amide or asulfonamide is employed as anitrogen source and potassium persulfate (K 2 S 2 O 8 )asanoxidant. Thus,the methyl CÀHbond of 43 can be amidated with trifluoroacetamide (44) to afford 45.C hen and co-workers used diphenyliodonium salt 47 to accomplish the C À Harylation of oxime 46 to give 48 (Scheme 9).…”

Section: Oximesmentioning

confidence: 99%

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

2017

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The functionalization of C(sp3)−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.

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Section: Oximesmentioning

confidence: 99%

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

2017

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“…With a more bulky silyl hydride such as t-BuMe 2 SiH, the silylated product was obtained only in low yield (Entry 5). Neither (EtO) 3 SiH nor (Me 3 Si)Me 2 SiH gave the silylated product at all under these reaction conditions.…”

mentioning

confidence: 85%

“…Directed catalytic functionalization of the sp 3 -CH bond is an attractive strategy for the synthesis of functionalized alkanes in organic synthesis. 1 Functional groups such as pyridyl, quinolinyl, oxazolinyl, carboxyl, aminocarbonyl, and imino groups are attached to alkanes as directing groups for CH functionalization through arylation, 2 amination, 3 silylation, 4 acetoxylation, 5 halogenation, 6 etc.…”

mentioning

confidence: 99%

“…1 Functional groups such as pyridyl, quinolinyl, oxazolinyl, carboxyl, aminocarbonyl, and imino groups are attached to alkanes as directing groups for CH functionalization through arylation, 2 amination, 3 silylation, 4 acetoxylation, 5 halogenation, 6 etc. Despite the remarkable acceleration of the catalytic reaction by the directing groups, the need for their installation in the substrates significantly limits the scope of the reaction.…”

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confidence: 99%

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Ruthenium-catalyzed C–H Silylation of Methylboronic Acid Using a Removable α-Directing Modifier on the Boron Atom

Ihara¹,

Ueda²,

Suginome

2011

Chemistry Letters

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Ruthenium-catalyzed CH silylation of methylboronic acid was achieved by use of 2-(1H-pyrazol-3-yl)aniline as a removable ¡-directing modifier on the boron atom. Crosscoupling of the product, i.e., (phenyldimethylsilyl)methylpinacolborane, with aryl halides proceeded in the presence of a [PdCl 2 (dppf)] catalyst and CsOH as a base.Directed catalytic functionalization of the sp 3 -CH bond is an attractive strategy for the synthesis of functionalized alkanes in organic synthesis.1 Functional groups such as pyridyl, quinolinyl, oxazolinyl, carboxyl, aminocarbonyl, and imino groups are attached to alkanes as directing groups for CH functionalization through arylation, 2 amination, 3 silylation, 4 acetoxylation, 5 halogenation, 6 etc. Despite the remarkable acceleration of the catalytic reaction by the directing groups, the need for their installation in the substrates significantly limits the scope of the reaction. It is likely that the development of "traceless" or "convertible" directing groups will make directed CH activation really useful and applicable to organic synthesis. 7 We have developed removable o-directing groups, which are attached to the boron atoms of arylboronic acids, for Ru-catalyzed o-CH silylation at their sp 2 -carbon atoms. 2-(1H-Pyrazol-3-yl)aniline and anthranilamide form six-membered diazaborine structures 1 and 2 containing NBN linkages upon condensation with arylboronic acids. 8,9 The nitrogen atoms in the attached directing group coordinate to the transition-metal catalysts and enable the CH functionalization at the orthopositions. It would be highly attractive if the strategy could be extended to activation of alkylboronic acids. In particular, such a synthetic strategy is most attractive for the synthesis of ¡-functionalized methylboronic acids (Figure 1), because they are not accessible by hydroboration unlike the higher alkylboronic acids. It has been shown that even strong bases are not able to abstract ¡-hydrogen atoms of methylboronic acid esters.10 It should be noted that, in spite of its potential usefulness, no catalytic CH-functionalization at the ¡-hydrogen of alkylboronic acids has been reported. Herein, we describe ¡-CH silylation of methylboronic acid using an ¡-directing modifier that is attached to the boron atom.Methylboronic acid was condensed with 2-(1H-pyrazol-3-yl)aniline and anthranilamide, giving MeB(pza) (1) and MeB(aam) (2), respectively, in high yields (eqs 1 and 2). A phenol analog MeB(pzp) (3) of 1 was also prepared by the reaction with commercially available 2-(1H-pyrazol-3-yl)phenol in high yield (eq 1). The modified methylboronic acids 13 were subjected to Ru-catalyzed reaction with triorganosilanes in the presence of norbornene as a hydrogen scavenger (Table 1).11 With the [RhCl(cod)] 2 catalyst, a trace amount of the expected ¡-silylation product was detected by 1 H NMR (Entry 1). Ruthenium catalysts were found to be more effective for ¡-silylation. The [RuH 2 (CO)(PPh 3 ) 3 ] catalyst, which served as the best catalyst in the o-CH silylation of PZA-and ...

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“…[26] In diesem Verfahren werden ein Amid oder ein Sulfonamid als Stickstoffquelle und Kaliumpersulfat (K 2 S 2 O 8 )a ls Oxidationsmittel eingesetzt. Somit kann die Methyl-C-H-Bindung von 43 mit Tr ifluoracetamid (44)u nter Bildung von 45 amidiert werden.…”

Section: Oximeunclassified

Komplementäre Strategien für die dirigierte C(sp³)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer

2017

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Funktionalisierungen von C(sp3)‐H‐Bindungen verkürzen und vereinfachen chemische Synthesen, indem sie die Verwendung einfacher Moleküle ermöglichen und neuartige Retrosynthesen bereitstellen. Intensive Forschungen, die auf die Entwicklung neuer Reaktionen basierend auf dem Ansatz der C‐H‐Funktionalisierung abzielten, haben zur weiten Verbreitung dieser Methoden in einer Vielzahl von Bereichen geführt. Dieser Aufsatz erörtert die Stärken und Schwächen der drei Hauptstrategien – übergangsmetallkatalysierte C‐H‐Aktivierung, 1,n‐Wasserstoffatomtransfer und übergangsmetallkatalysierter Carben‐ oder Nitrentransfer – in der gezielten Funktionalisierung nichtaktivierter C(sp3)‐H‐Bindungen. Für jede Strategie werden der Anwendungsbereich, die Reaktivität verschiedener C‐H‐Bindungen, die Position der reagierenden C‐H‐Bindungen bezüglich der dirigierenden Gruppe und die stereochemischen Auswirkungen mit Beispielen aus der Literatur veranschaulicht. Das Ziel dieses Aufsatzes ist es, dem Anwender von C‐H‐Funktionalisierungsreaktionen eine Orientierungshilfe zu geben und künftige Forschungen auf diesem Gebiet anzuregen.

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Intermolecular Amidation of Unactivated sp² and sp³ C−H Bonds via Palladium-Catalyzed Cascade C−H Activation/Nitrene Insertion

Cited by 660 publications

References 28 publications

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Ruthenium-catalyzed C–H Silylation of Methylboronic Acid Using a Removable α-Directing Modifier on the Boron Atom

Komplementäre Strategien für die dirigierte C(sp³)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer

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Intermolecular Amidation of Unactivated sp2 and sp3 C−H Bonds via Palladium-Catalyzed Cascade C−H Activation/Nitrene Insertion

Cited by 660 publications

References 28 publications

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Ruthenium-catalyzed C–H Silylation of Methylboronic Acid Using a Removable α-Directing Modifier on the Boron Atom

Komplementäre Strategien für die dirigierte C(sp3)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer

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Intermolecular Amidation of Unactivated sp² and sp³ C−H Bonds via Palladium-Catalyzed Cascade C−H Activation/Nitrene Insertion

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Complementary Strategies for Directed C(sp³)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

Komplementäre Strategien für die dirigierte C(sp³)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer