Profound Steric Control of Reactivity in Aryl Halide Addition to Bisphosphane Palladium(0) Complexes

Galardon, Erwan; Ramdeehul, Shailesh; Brown, John M.; Cowley, Andrew; Hii, King Kuok; Jutand, Anny

doi:10.1002/1521-3757(20020517)114:10<1838::aid-ange1838>3.0.co;2-v

Cited by 42 publications

(15 citation statements)

References 22 publications

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“…More recently, Brown and co‐workers59 showed the mechanism of oxidative addition to [Pd(PR 3 ) 2 ] complexes to be highly sensitive to the bulkiness of PR 3 (where PR 3 =PCy n t Bu 3− n , n =0, 1, 2, 3). Complexes with PR 3 =P t Bu 3 or PCy t Bu 2 undergo oxidative addition with aryl halides by a dissociative mechanism, whereas [Pd(PR 3 ) 2 ] complexes with the less bulky phosphines PCy 2 t Bu and PCy 3 follow an associative mechanism.…”

Section: Mechanistic Studiesmentioning

confidence: 99%

Monoligated Palladium Species as Catalysts in Cross‐Coupling Reactions

2004

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Palladium-mediated cross-coupling reactions are attractive organometallic transformations for the generation of C--C, C--N, C--O, and C--S bonds. Despite being widely employed in small-scale syntheses, cross-coupling reactions have not found important industrial applications because until recently, only reactive aryl bromides and iodides could be used as substrates. These substrates are generally more expensive and less widely available than their chloride counterparts. Over the past few years, new catalytic systems with the ability to activate unreactive and sterically hindered aryl chlorides have been developed. The new catalysts are based on palladium complexes that contain electron-rich and bulky phosphine or carbene ligands. The enhanced reactivity observed with these new systems has been attributed to the formation of unsaturated and reactive [PdL] species which can readily undergo oxidative addition reactions with ArX to yield [Pd(Ar)X(L)].

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Section: Mechanistic Studiesmentioning

confidence: 99%

Monoligated Palladium Species as Catalysts in Cross‐Coupling Reactions

2004

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“…Our previous studies indicated that a catalyst system based on Pd/2‐dicyclohexylphosphino‐2′,4′,6′‐triisopropylbiphenyl (XPhos; 1 ; Cy=cyclohexyl) demonstrated both a greater degree of activity and stability than those derived from our previous generations of ligands 6. The substitution of the 2′,2′‐positions on the lower aromatic ring prevents palladacycle formation,7 and the added bulk causes the equilibrium to shift from that favoring [L 2 Pd 0 ] to one in which [L 1 Pd 0 ] predominates, thus facilitating all steps in the catalytic cycle 7–10…”

Section: Ligands Used For the Coupling Of 4‐chlorophenol And N‐hexylamentioning

confidence: 99%

Monodentate Phosphines Provide Highly Active Catalysts for Pd‐Catalyzed CN Bond‐Forming Reactions of Heteroaromatic Halides/Amines and (H)N‐Heterocycles

et al. 2006

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A good alternative: Highly reactive catalysts based on palladium and dialkylbiarylphosphino ligands provide unprecedented reactivity and selectivity in CN bond‐forming processes. The bulky monophosphine catalyst system Pd/1 was effective for the reaction of aryl/heteroaryl halides bearing primary amides and 2‐aminoheterocycles (see scheme; dba=dibenzylideneacetone, R=CONH2, NH2), thus showing that monodentate phosphines are viable alternatives to, and sometimes superior to, chelating ligands.

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Section: Ligands Used For the Coupling Of 4‐chlorophenol And N‐hexylamentioning

confidence: 99%

Monodentate Phosphines Provide Highly Active Catalysts for Pd‐Catalyzed CN Bond‐Forming Reactions of Heteroaromatic Halides/Amines and (H)N‐Heterocycles

et al. 2006

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Eine gute Alternative: Hoch reaktive Palladium‐Dialkylbiarylphosphanyl‐Katalysatoren ergeben bislang unerreichte Reaktivitäten und Selektivitäten bei der C‐N‐Verknüpfung. Der voluminöse Monophosphan‐Katalysator Pd/1 eignet sich zur Umsetzung von Halogen(het)arenen, die primäre Amide tragen, und 2‐Aminoheterocyclen (siehe Schema; dba=Dibenzylidenaceton, R=CONH2, NH2). Einzähnige Phosphane können Chelatliganden also ebenbürtig, manchmal gar überlegen sein.

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Profound Steric Control of Reactivity in Aryl Halide Addition to Bisphosphane Palladium(0) Complexes

Cited by 42 publications

References 22 publications

Monoligated Palladium Species as Catalysts in Cross‐Coupling Reactions

Monoligated Palladium Species as Catalysts in Cross‐Coupling Reactions

Monodentate Phosphines Provide Highly Active Catalysts for Pd‐Catalyzed CN Bond‐Forming Reactions of Heteroaromatic Halides/Amines and (H)N‐Heterocycles

Monodentate Phosphines Provide Highly Active Catalysts for Pd‐Catalyzed CN Bond‐Forming Reactions of Heteroaromatic Halides/Amines and (H)N‐Heterocycles

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