Palladium-Catalyzed Intramolecular Addition of 1,3-Diones to Unactivated Olefins

Pei, Tao; Widenhoefer, Ross A.

doi:10.1021/ja011764x

Cited by 138 publications

(61 citation statements)

References 19 publications

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“…Kürzlich wurden mehrere atomökonomische Ansätze entwickelt, die eine metallkatalysierte Addition der 1,3-Dicarbonylverbindung an nichtaktivierte Alkene, [177,178] Alkine [179][180][181][182][183] und 1,6-Enine [184] vorsehen. Es wurde berichtet, dass der Gold(I)-Komplex in [Au-(PPh 3 )]OTf ein effizienter Katalysator für die Carbocyclisierung von b-Ketoestern mit angebundenen Alkinen (ConiaEn-Reaktion) ist und zur Bildung von funktionalisierten Fünfringen unter milden und neutralen Bedingungen verhilft (1 Mol-% Katalysator, Raumtemperatur).…”

Section: Elektronenreiche Alkene Und Enolate Als Nucleophileunclassified

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

2010

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Der steigende Bedarf an neuen selektiven und umweltverträglichen Methoden in der organischen Synthese treibt die Entwicklung effizienterer Reaktionssysteme an. In diesem Zusammenhang hat man sich häufig auf Übergangsmetalle, Liganden und Additive konzentriert; dem Gegenion des Metallkations wurde weniger Aufmerksamkeit geschenkt. Kürzlich wurden Metallsalze mit einem oder mehreren Triflimidat‐Gegenion(en) (Tf2N−) beschrieben. Triflimidate bilden eine einzigartige Katalysatorklasse mit außergewöhnlicher σ‐ und π‐Lewis‐Acidität, die durch die starke Delokalisierung der Ladung im Triflimidation sowie seine sterische Hinderung begründet wird. Daher wird praktisch kein nucleophiles Verhalten und eine hohe positive Ladungsdichte am Metallkation beobachtet, die seine Lewis‐Acidität verstärkt. Folglich sind Metalltriflimidate häufig effizienter als entsprechende ‐halogenide oder ‐triflate. Dieser Aufsatz beschreibt Methoden zur Herstellung von Metalltriflimidaten und deren Einsatz als Katalysatoren.

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Section: Elektronenreiche Alkene Und Enolate Als Nucleophileunclassified

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

2010

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“…As noted in the Introduction, it was also our expectation that alkenyl β-diketone 1 would undergo oxidative alkylation in the presence of a Pd(II) complex. However, treatment of 1 with a stoichiometric amount of PdCl 2 (CH 3 CN) 2 (2) in THF at room temperature for 15 min led not to oxidative alkylation, but rather to hydroalkylation with formation of 2-acetylcyclohexanone (3) in 70 % isolated yield (Scheme 1) [13]. Because hydroalkylation is a redoxneutral process, we realized that no oxidant should be required for the catalytic conversion of 1 to 3.…”

Section: Hydroalkylation Of 3-butenyl ␤-Diketonesmentioning

confidence: 98%

“…Because hydroalkylation is a redoxneutral process, we realized that no oxidant should be required for the catalytic conversion of 1 to 3. Indeed, treatment of 1 with a catalytic amount of 2 (10 mol %) in dioxane at room temperature for 16 h led to the isolation of 3 in 81 % yield as a single regioisomer (Scheme 1) [13]. Palladium-catalyzed hydroalkylation of 3-butenyl β-diketones tolerated substitution at the terminal acyl group, the α-carbon atom, and at the terminal olefinic position, but not at the allylic and homoallylic positions (Table 1) …”

Section: Hydroalkylation Of 3-butenyl ␤-Diketonesmentioning

confidence: 99%

Palladium-catalyzed alkylation of unactivated olefins

Widenhoefer

2004

Pure and Applied Chemistry

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Reaction of a 3-butenyl β-diketone with a catalytic amount of PdCl 2 (CH 3 CN) 2 in dioxane at room temperature led to olefin hydroalkylation and formation of the corresponding 2-acylcyclohexanone in good yield as a single regioisomer. Deuterium-labeling experiments for the hydroalkylation of 7-octene-2,4-dione were in accord with a mechanism involving outer-sphere attack of the pendant enol on a palladium-complexed olefin to form a palladium cyclohexyl species, followed by palladium migration via iterative β-hydride elimination/addition and protonolysis from a palladium enolate complex. In comparison to a 3-butenyl β-diketone, reaction of a 4-pentenyl β-diketone with a catalytic amount of PdCl 2 (CH 3 CN) 2 in the presence of CuCl 2 led to oxidative alkylation and formation of the corresponding 2-acyl-3-methyl-2-cyclohexenone in good yield as a single isomer. Unactivated olefins tethered to less reactive carbon nucleophiles such as β-keto esters, α-aryl ketones, and even dialkyl ketones underwent palladium-catalyzed hydroalkylation in the presence of Me 3 SiCl or HCl to form the corresponding cyclohexanones in moderate-to-good yield with high regioselectivity.

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“…(1)]. [1,2] For example, treatment of 7-octene-2,4-dione (1) with a catalytic amount of PdCl 2 (CH 3 CN) 2 (2; 10 mol %) in dioxane at room temperature for 16 h led to the formation of 2-acetylcyclohexanone (3) in 81 % yield as a single regioisomer [Eq. (1)].…”

Section: Introductionmentioning

confidence: 99%

“…[1,2] For example, treatment of 7-octene-2,4-dione (1) with a catalytic amount of PdCl 2 (CH 3 CN) 2 (2; 10 mol %) in dioxane at room temperature for 16 h led to the formation of 2-acetylcyclohexanone (3) in 81 % yield as a single regioisomer [Eq. (1)]. [1] Similarly, we have reported the palladium-catalyzed intramolecular oxidative alkylation of 4-pentenyl b-diketones to form 2-acyl-2-cyclohexenones [Eq.…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Catalyzed Intramolecular Hydroalkylation of Alkenyl‐ β‐Keto Esters, α‐Aryl Ketones, and Alkyl Ketones in the Presence of Me₃SiCl or HCl

Han¹,

Wang²,

Pei³

et al. 2004

Chemistry A European J

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Reaction of 3-butenyl beta-keto esters or 3-butenyl alpha-aryl ketones with a catalytic amount of [PdCl2(CH3CN)2] (2) and a stoichiometric amount of Me3SiCl or Me3SiCl/CuCl2 in dioxane at 25-70 degrees C formed 2-substituted cyclohexanones in good yield with high regioselectivity. This protocol tolerated a number of ester and aryl groups and tolerated substitution at the allylic, enolic, and cis and trans terminal olefinic positions. In situ NMR experiments indicated that the chlorosilane was not directly involved in palladium-catalyzed hydroalkylation, but rather served as a source of HCl, which presumably catalyzes enolization of the ketone. Identification of HCl as the active promoter of palladium-catalyzed hydroalkylation led to the development of an effective protocol for the hydroalkylation of alkyl 3-butenyl ketones that employed sub-stoichiometric amounts of 2, HCl, and CuCl2 in a sealed tube at 70 degrees C.

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Palladium-Catalyzed Intramolecular Addition of 1,3-Diones to Unactivated Olefins

Cited by 138 publications

References 19 publications

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

Palladium-catalyzed alkylation of unactivated olefins

Palladium‐Catalyzed Intramolecular Hydroalkylation of Alkenyl‐ β‐Keto Esters, α‐Aryl Ketones, and Alkyl Ketones in the Presence of Me₃SiCl or HCl

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Palladium-Catalyzed Intramolecular Addition of 1,3-Diones to Unactivated Olefins

Cited by 138 publications

References 19 publications

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

Metalltriflimidate sind bessere Katalysatoren für die organische Synthese als Metalltriflate – der Effekt eines stark delokalisierten Gegenions

Palladium-catalyzed alkylation of unactivated olefins

Palladium‐Catalyzed Intramolecular Hydroalkylation of Alkenyl‐ β‐Keto Esters, α‐Aryl Ketones, and Alkyl Ketones in the Presence of Me3SiCl or HCl

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Palladium‐Catalyzed Intramolecular Hydroalkylation of Alkenyl‐ β‐Keto Esters, α‐Aryl Ketones, and Alkyl Ketones in the Presence of Me₃SiCl or HCl