Alkene Coupling through Triflic Acid Elimination on Platinum(II)

Szuromi, Endre; Sharp, Paul R.

doi:10.1021/om0507631

Cited by 24 publications

(39 citation statements)

References 15 publications

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“…While it is difficult to draw conclusions on the validity of these alkylgold(I) complexes as intermediates in the reported alkene hydroamination reactions, these results are in accord with the hypothesis that the gold(I)-promoted addition of amines to alkenes is reversible. It is possible that under catalytic conditions the formation of an alkylgold complex merely serves to liberate an equivalent of Brønsted acid, 27 which catalyzes the observed hydroamination reactions.…”

Section: Resultsmentioning

confidence: 99%

Alkylgold complexes by the intramolecular aminoauration of unactivated alkenes

et al. 2010

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Alkylgold(I) complexes were formed from the gold(I)-promoted intramolecular addition of various amine nucleophiles to alkenes. These experiments provide the first direct experimental evidence for the elementary step of gold-promoted nucleophilic addition to an alkene. Deuterium-labeling studies and X-ray crystal structures provide support for a mechanism involving anti-addition of the nucleophile to a gold-activated alkene, which is verified by DFT analysis of the mechanism. Ligand studies indicate that the rate of aminoauration can be drastically increased by use of electron-poor arylphosphines, which are also shown to be favored in ligand exchange experiments. Attempts at protodeauration lead only to recovery of the starting olefins, though the gold can be removed under reducing conditions to provide the purported hydroamination products.

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Section: Resultsmentioning

confidence: 99%

Alkylgold complexes by the intramolecular aminoauration of unactivated alkenes

et al. 2010

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“…Szuromi und Sharp beschrieben kürzlich die stöchiometrische Dimerisierung von Alkenen in Gegenwart von [(cod)Pt(OTf) 2 ], die nach Eliminierung von Trifluormethansulfonsäure zu Platinalkylen oder Platin‐π‐allylen führt (Schema ) 126. Es wurde angenommen, dass die Reaktion entweder über eine Aktivierung der vinylischen CH‐Gruppe mit anschließender Olefininsertion verläuft (nicht gezeigt), oder über einen Outer‐Sphere‐Angriff eines Olefins an einem komplexierten Olefin mit anschließender Eliminierung von HOTf aus einem carbokationischen Intermediat.…”

Section: Katalyseunclassified

Highly Stereoselective Total Synthesis of Fully Hydroxy‐Protected Mycolactones A and B and Their Stereoisomerization upon Deprotection

Wang

Yin

Negishi

2011

Chemistry A European J

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Unprecedentedly efficient and highly (≥98%) stereoselective syntheses of mycolactones A and B sidechains relied heavily on Pd-catalyzed alkenylation (Negishi version) and were completed in 11 longest linear steps from ethyl (S)-3-hydroxybutyrate in 12% and 11% overall yields, respectively, roughly corresponding to an average of 82% yield per step. The synthesis of mycolactone core was realized by using Pd-catalyzed alkenyl–allyl coupling and an epoxide-opening reaction with a trialkylalkenylaluminate as key steps. Fully hydroxy-protected mycolactones A and B of ≥98% isomerical purity were synthesized successfully for the first time. However, unexpected 4/3-5/4 inseparable mixtures of mycolactones A and B were obtained upon deprotection.

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“…[125] Szuromi and Sharp have recently demonstrated that several alkenes undergo stoichiometric dimerization in the presence of [(cod)Pt(OTf) 2 ] to give Pt-alkyl or Pt-p-allyl complexes, with the elimination of triflic acid (Scheme 17). [126] It was proposed that the reactions proceed by either vinylic CÀH bond activation followed by olefin insertion (not shown), or by outer-sphere attack of one olefin on a complexed olefin followed by elimination of HOTf from a carbocationic intermediate. The generation of Pt-alkyl or Pt-p-allyl complexes by olefin dimerization and acid elimination may provide a useful model for the future development of catalytic transformations based on the activation of olefins.…”

Section: Homogeneous Platinum Catalysismentioning

confidence: 99%

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

2007

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The electrophilic activation of alkenes by transition-metal catalysts is a fundamental step in a rapidly growing number of catalytic processes. Although palladium is the best known metal for this purpose, the special properties of its third-row cousin platinum (strong metal-ligand bonds and slow substitution kinetics) have enabled the development of transformations that are initiated by addition to the C=C bonds by protic carbon, nitrogen, oxygen, and phosphorus nucleophiles, as well as alkene or arene nucleophiles. Additionally, reactivity profiles, which are often unique to platinum, provide wholly new reaction products. This Review concerns platinum-catalyzed electrophilic alkene activation reactions, with a special emphasis on the mechanistic properties of known systems, on the differences between platinum and palladium catalysts, and on the prospects for the development of new systems.

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Alkene Coupling through Triflic Acid Elimination on Platinum(II)

Abstract: The Pt(II) complexes (1,5-COD)Pt(OTf)2 and [(COD)Pt(THF)(OTf)]OTf react readily with alkenes (ethylene, cyclopentene, norbornenes) to give coupling products via HOTf elimination. With propylene a simple allyl complex is obtained.

Cited by 24 publications

References 15 publications

Alkylgold complexes by the intramolecular aminoauration of unactivated alkenes

Alkylgold complexes by the intramolecular aminoauration of unactivated alkenes

Highly Stereoselective Total Synthesis of Fully Hydroxy‐Protected Mycolactones A and B and Their Stereoisomerization upon Deprotection

Electrophilic Activation of Alkenes by Platinum(II): So Much More Than a Slow Version of Palladium(II)

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