"Pd(C6F5)Br", a convenient precursor for studying the endo attack of nucleophiles on olefins. X-ray structure of bis(.mu.-bromo)bis(4-(pentafluorophenyl)-1-3-.eta.3-cyclohexenyl)dipalladium(II)

Albéniz, Ana C.; Espinet, Pablo; Foces‐Foces, C.; Cano, F. H.

doi:10.1021/om00118a027

Cited by 47 publications

(44 citation statements)

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“…The cyclohexenyl moieties in 13 have a trans arrangement and a pseudoboat conformation with the bulky pentafluorophenyl groups in the equatorial position. The Pd-allyl bond lengths found here are comparable to other palladium h 3 -cyclohexenyl structures, [17,19] but the allyl moiety is asymmetrically coordinated: a larger PdÀC(allyl) bond length trans to the shorter Pd-C(bridging aryl) bond is found (PdÀC (9), 2.176 versus Pd À C (7), 2.129 ). The short Pd À Pd bond length in the dimer (2.6897 ) suggests some degree of metal ± metal interaction.…”

Section: Synthesis and Decomposition Experiments Of Plausible Transmesupporting

confidence: 80%

“…Reactions of cyclohexenyl derivatives with Bu 3 SnRf (Rf C 6 Cl 2 F 3 ): The reaction of cyclohexenyl bromide and Bu 3 SnRf (1, Rf dichlorotrifluorophenyl) in chloroform at 50 8C, catalyzed by 2.5 % of the h 3 -allyl palladium complex di-mbromobis(5-pentafluorophenyl-1-3-h 3 -cyclohexenyl)-dipalladium(ii) (2), [17] slowly gave the coupling product 3-(dichlorotrifluorophenyl)-cylohexene (3) (Scheme 3, 46 % yield after 14 days).…”

Section: Resultsmentioning

confidence: 99%

“…solution of 13 is warmed to 50 8C in CDCl 3 the signals in the 19 F NMR spectrum become broad, indicating slow interconversion of the two isomers, probably by bridge splitting and reforming, as observed for 2 and for related halogen-bridged allyl complexes. [17,23] The dimeric structure of 13 is maintained in solvents of low to moderate coordination ability (CHCl 3 , CH 2 Cl 2 , acetone, and Et 2 O), but acetonitrile splits the bridges to give 10, as stated above.…”

Section: Synthesis and Decomposition Experiments Of Plausible Transmementioning

confidence: 98%

“…[3,16,17] In this paper, by using fluorinated aryl derivatives we have been able to detect complex B (Scheme 1) in the course of a coupling reaction, as well as some other species involved in the catalytic cycle or closely related to it. We examine in detail the stoichiometric and catalytic coupling of cyclohexen-3-yl derivatives and tributyl(dichlotrifluorophenyl)tin, analyzing the pathways that compete with it, and finding the conditions that make the coupling efficient.…”

Section: B Cmentioning

confidence: 99%

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The Pd-Catalyzed Coupling of Allyl Halides and Tin Aryls: Why the Catalytic Reaction Works and the Stoichiometric Reaction Does Not

2001

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Arylallylpalladium complexes [Pd(5-C6F5-eta3-cyclohexenyl)(C6Cl2F3)(NCMe)] (10) and [Pd2(mu-C6Cl2F3)2(5-C6F5-1,3-eta3-cyclohexenyl)2] (13) have been synthesized. Complex 13 is an example of a rare class of metal complexes with aryl bridges and its X-ray crystal diffraction structure has been determined. These arylallylpalladium complexes are involved in the coupling of Bu3SnRf (1, Rf = dichlorotrifluorophenyl) and [Pd2(mu-Br)2(5-C6F5-1,3-eta3-cyclohexenyl)2] (2); complex 10 has been detected in the course of the stoichiometric coupling reaction in acetonitrile. Decomposition experiments of 10 and 13 in different conditions, and comparison with the reactions of 1 and 2, allow us to determine that reductive elimination does not occur in the absence of additives. p-Benzoquinone coordinates to Pd to give complex 15 and promotes reductive elimination to give the coupling products selectively. The outcome of the coupling reaction is controlled by the reductive elimination step, but the overall rate is controlled by the faster preequilibrium, which determines the concentration of 10 or 13. Palladium-catalyzed coupling of allyl halides and tin aryls works better than the stoichiometric allyl-aryl reductive coupling on isolated allylarylpalladium complexes, because they benefit from the presence in the solution of substrate allylic halides acting as electron-withdrawing olefins and promoting reductive elimination. More efficient allyl-aryl couplings, whether stoichiometric or catalytic, can be achieved upon addition of p-benzoquinone to the reaction mixture in a noncoordinating solvent.

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Section: Synthesis and Decomposition Experiments Of Plausible Transmesupporting

confidence: 80%

Section: Resultsmentioning

confidence: 99%

Section: Synthesis and Decomposition Experiments Of Plausible Transmementioning

confidence: 98%

Section: B Cmentioning

confidence: 99%

See 2 more Smart Citations

The Pd-Catalyzed Coupling of Allyl Halides and Tin Aryls: Why the Catalytic Reaction Works and the Stoichiometric Reaction Does Not

2001

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“…86,87 19 F NMR spectroscopy offers a very convenient tool to study these reaction since the chemical shift difference of the ortho fluorine in polyfluorinated aryls change about 20 ppm upfield on going from a Pd-Ar F to a C-Ar F linkage. 202 In this way we have studied many stoichiometric examples of insertion of an alkene into the Pd-C 6 F 5 bond. …”

Section: 1-insertionmentioning

confidence: 99%