Kinetic Study of Reductive Elimination from the Complexes (Diphosphine)Pd(R)(CN)

Marcone, John E.; Moloy, Kenneth G.

doi:10.1021/ja980762i

Cited by 159 publications

(127 citation statements)

References 23 publications

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“…Als Erklärung wurde vorgeschlagen, dass der sperrige zweizähnige Ligand die unerwünschte b-HydridEliminierung aus dem transmetallierten Komplex [Pd(dppf)-(Alkyl)(Vinyl)] verlangsamt, [159] während der große Bisswinkel des Liganden die Geschwindigkeit der konkurrierenden reduktiven Eliminierung erhöht, die zur Bildung des Produkts führt. [160] Der a-Iodenon-Kupplungspartner 171 wurde in wenigen Stufen aus der tricyclischen Verbindung 170 hergestellt, die ihrerseits durch eine andere palladiumkatalysierte Kupplung -die intramolekulare Heck-Cyclisierung der antiAldol-Vorstufe 169 -synthetisiert wurde (Schema 32 . [156] C-C-Kupplungen…”

Section: Suzuki-reaktionenunclassified

Palladiumkatalysierte Kreuzkupplungen in der Totalsynthese

2005

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Wenn man die Entwicklung der organischen Chemie betrachtet, kommt man schnell zu dem Schluss, dass kein Reaktionstyp dieses Gebiet in vergleichbarer Weise geprägt hat wie die Kohlenstoff‐Kohlenstoff‐Kupplungen. Grignard‐, Diels‐Alder‐ und Wittig‐Reaktionen sind nur drei herausragende Beispiele für solche Prozesse, die im vergangenen Jahrhundert zweifellos entscheidend am Aufstieg der chemischen Synthese beteiligt waren. Im letzten Viertel des 20. Jahrhunderts bereicherte eine neue Familie von leistungsfähigen Reaktionen zur Knüpfung von Kohlenstoff‐Kohlenstoff‐Bindungen das Repertoire der Synthesechemie: die übergangsmetallkatalysierten Reaktionen, allen voran die palladiumkatalysierten Kreuzkupplungen. In diesem Aufsatz werden Auszüge aus einer Reihe von ausgewählten Synthesen diskutiert. Die Beispiele sollen die enorme Leistungsfähigkeit dieser Prozesse in der Kunst der Totalsynthese aufzeigen und ihr Potenzial für zukünftige chemische Synthesen unterstreichen.

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Section: Suzuki-reaktionenunclassified

Palladiumkatalysierte Kreuzkupplungen in der Totalsynthese

2005

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“…20 . In concert with the above changes, the C=C bond length of the palladium-bound olefinic moiety increases from 1.388 Å (1) to 1.420 Å (3), which is suggestive of an increase in back-donation from the Pd centre to the * C=C orbital (see below).…”

Section: Addition Of a Second Equivalent Of L1 To [Pdme 2 (κ 2 -Pc-lmentioning

confidence: 99%

Combined DFT and experimental studies of C–C and C–X elimination reactions promoted by a chelating phosphine–alkene ligand: the key role of penta-coordinate PdII

Estévez¹,

Tuxworth²,

Sotiropoulos³

et al. 2014

Dalton Trans.

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Citation for published item:ist¡ evezD v ur nd uxworthD vuke F nd otiropoulosD te nEw r nd hyerD hilip F hyer nd wiqueuD u rinne @PHIRA 9gom ined hp nd experiment l studies of g!g nd g! elimin tion re tions promoted y hel ting phosphine! lkene lig nd X the key role of pent E oordin te dssF9D h lton tr ns tionsFD RQ @PWAF ppF IIITSEIIIUWF Further information on publisher's website:httpXGGdxFdoiForgGIHFIHQWG RdtHHQRH Publisher's copyright statement: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

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“…It is now commonly accepted that an increase of the PMP angle in [Pd(phosphine) 2 XY] complexes favours the reductive elimination step in C À C coupling reactions. [46][47][48] Formation of such species do, of course, not prevent from forming P,O-chelated intermediates.…”

Section: ·Hmentioning

confidence: 99%

“…The increased performance of 3 vs. that of 2 possibly arises from its partial conversion into P,P-chelate complexes in which the ligand displays a large bite angle, [49] this latter feature being known, as already mentioned above, to promote reductive elimination in cross-coupling reactions. [46][47][48] Molecular mechanics calculations (SPAR-TAN) indeed show that in hypothetical [PdX 2 (3)] chelate complexes (X = halide, aryl), be they square planar or tetrahedral, the corresponding PMP angles are significantly larger than in conventional ML 2 X 2 complexes. Here the resulting strain generated within [a]…”

Section: ·Hmentioning

confidence: 99%

Resorcin[4]arene‐Derived Mono‐ and Diphosphines in Suzuki Cross‐Coupling

et al. 2010

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Three resorcin [4]arene cavitands (1-3) having either one or two resorcinolic C-2 atoms substituted by a À CH 2 PPh 2 podand arm were assessed in the Suzuki arylation of aryl bromides with phenylboronic acid. Using P:Pd ratios of 2:1 and operating in dioxane at 100 8C with a catalyst loading of 0.001 mol% resulted in highly efficient catalytic systems. For example, TOFs up to 34570 mol(converted ArBr)·mol(Pd) À1 ·h À1 were obtained with the proximally-disubstituted cavitand 3 when using 4-bromotoluene as substrate. The performance was shown to vary in the following order: monophosphine 1 < diphosphine 2 < diphosphine 3 (where 2 is the distally disubstituted cavitand). A comparison of the catalytic properties of monophosphine-cavitand 1 with those of benzyldiphenylphosphine and o-anisylmethyldiphenyl phosphine suggests that 1 functions as a hemilabile phosphine, the oxygen atoms close to the phosphorus atom behaving as donors able to temporarily increase the electron density on the metal and/ or favour the formation of mono-ligand Pd(0) species.

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Kinetic Study of Reductive Elimination from the Complexes (Diphosphine)Pd(R)(CN)

Cited by 159 publications

References 23 publications

Palladiumkatalysierte Kreuzkupplungen in der Totalsynthese

Palladiumkatalysierte Kreuzkupplungen in der Totalsynthese

Combined DFT and experimental studies of C–C and C–X elimination reactions promoted by a chelating phosphine–alkene ligand: the key role of penta-coordinate PdII

Resorcin[4]arene‐Derived Mono‐ and Diphosphines in Suzuki Cross‐Coupling

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