Palladium catalyzed Suzuki coupling reactions using cobalt-containing bulky phosphine ligands

Hong, Fung‐E; Ho, Yi-Jung; Chang, Yu‐Chang; Lai, Yi‐Chun

doi:10.1016/j.tet.2004.01.071

Cited by 28 publications

(10 citation statements)

References 24 publications

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“…The palladium catalyst derived from phosphine ligand 4 with Cy substituent was noticeably more reactive than that derived from Ph substituent (less bulky and electron-rich ligand) reported earlier [10]. As shown above, both activated and unactivated aryl bromides can be coupled with arylboronic acids in the presence of 1% 4/Pd(OAc) 2 (1:1) complex.…”

Section: Suzuki Reaction Using Cobalt-containing Phosphine Ligand 4 Wmentioning

confidence: 63%

“…Similar observations of spectroscopic data are perceived in the case of 5. In 1 H NMR, a large downfield shift for one of the methylene protons at 5.96 ppm is observed due to the weak intramolecular hydrogen bonding between the oxide and the adjacent methylene proton [10]. The 31 P NMR spectrum of 5 shows two singlets in the ratio of 1:2 at 50.2 and 36.0 ppm for three phosphorous atoms and large downfield shifts are observed for the oxidized phosphorous atoms.…”

Section: Preparation Of Cobalt-containing Monodentate Phosphine Ligandsmentioning

confidence: 95%

“…Our previous works had demonstrated that several alkyne-bridged, dicobalt complexed, monodentate phosphines, [(l-PPh 2 CH 2 PPh 2 )Co 2 (CO) 4 ][l,g-RC"CPPh 2 ] (1a: R = Ph; 1b: R = CMe 3 ; 1c: R = SiMe 3 ), acted as potential bulky ligands in the palladium-catalyzed Suzuki coupling reaction [10]. It is known that a palladium complex is more air-stable when it is coordinated by a phosphine with cyclohexyl substituent than that of tert-butyl one [1e].…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen atoms are omitted for clarity. Selected bond lengths (Å ) and bond angles (°)2)-C(2) 1.936(10), Co(2)-C(1) 1.971(10), Co(2)-P(3) 2.249(3), P(1)-C(1) 1.826(10), P(2)-C(49) 1.839(10), P(3)-C(49) 1.817(9), C(1)-C(2) 1.343(12), C(2)-C(3) 1.494(13), C(1)-Co(1)-C(2) 40.2(4), P(2)-Co(1)-Co(2) 100.31(9), C(2)-Co(2)-C(1) 40.2(4), P(3)-Co(2)-Co(1) 89.89(9), C(49)-P(2)-Co(1) 109.3(3), C(49)-P(3)-Co(2) 110.4(3), C(2)-C(1)-P(1) 135.5(8), Co(1)-C(1)-Co(2) 78.7(4), C(1)-C(2)-C(…”

mentioning

confidence: 99%

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Synthesis of cobalt-containing monodentate phosphine ligand and application toward Suzuki cross-coupling reactions

Hong

Chang

et al. 2005

Journal of Organometallic Chemistry

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Section: Suzuki Reaction Using Cobalt-containing Phosphine Ligand 4 Wmentioning

confidence: 63%

Section: Preparation Of Cobalt-containing Monodentate Phosphine Ligandsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Synthesis of cobalt-containing monodentate phosphine ligand and application toward Suzuki cross-coupling reactions

Hong

Chang

et al. 2005

Journal of Organometallic Chemistry

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“…These results are consistent with those obtained by other authors using similar heterocyclic substrates. [29,30] …”

Section: Suzuki Reaction With Heterocyclic Brominated Derivativesmentioning

confidence: 99%

Suzuki cross‐coupling reaction of aryl and heterocyclic bromides and aromatic polybromides on a Pd(II)‐hydrotalcite catalyst

Mora¹,

Jiménez‐Sanchidrián²,

Ruíz³

2008

Applied Organom Chemis

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The Suzuki cross-coupling reaction of various bromine-containing substrates and phenylboronic acid in toluene at 90• C on a Pd(AcO) 2 Py 2 catalyst supported on an Mg-Al hydrotalcite, using K 2 CO 3 as the base, was studied. The conversion and selectivity results obtained for many of the substrates were excellent and similar to those provided by more active or even homogeneous catalysts. The reactions of aryl polybromides and phenylboronic acid gave the corresponding polyaromatic compounds in variable yields depending on the particular substrate. Arylation occurred in a consecutive manner by substitution of the different Br atoms. ICP-MS measurements of the palladium content of the catalyst performed prior to and after the reaction revealed that part of the metal is incorporated into the bulk solution; therefore, the catalytic process is not purely heterogeneous.

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Experimental and DFT Study of the Tautomeric Behavior of Cobalt‐Containing Secondary Phosphine Oxides

Wei

Huang

et al. 2007

Chemistry A European J

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New cobalt-containing secondary phosphine oxides [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(4){mu,eta-PhC[triple chemical bond]CP(==O)(H)(R)}] (8 a: R=tBu; 8 b: R=Ph) were prepared by reaction of secondary phosphine oxides PhC[triple chemical bond]CP- (==O)(H)(R) (6 a: R=tBu; 6 b: R=Ph) with dppm-bridged dicobalt complex [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(6)] (2). The molecular structures of 8 a and 8 b were determined by single-crystal X-ray diffraction. Although palladium-catalyzed Heck reactions employing 8 b as ligand gave satisfying results, 8 a performed poorly in the same reaction. Judging from these results, a tautomeric equilibrium between 8 b and its isomeric form [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(4){mu,eta-PhC[triple chemical bond]CP(OH)(Ph)}] 8 b' indeed takes place, but it is unlikely between 8 a and [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(4){mu,eta-PhC[triple chemical bond]CP(OH)(tBu)}] (8 a'). The DFT studies demonstrated that reasonable activation energies for the tautomeric conversions can be achieved only via a bimolecular pathway. Since a tBu group is much larger than a Ph group, the conversion is presumably only feasible in the case of 8 bright harpoon over left harpoon8 b', but not in the case of 8 aright harpoon over left harpoon8 a'. Another cobalt-containing phosphine, namely, [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(4){mu,eta-PhC[triple chemical bond]CP(NEt(2))(tBu)}] (7 a), and its oxidation product [(mu-PPh(2)CH(2)PPh(2))Co(2)(CO)(4){mu,eta-PhC[triple chemical bond]CP(==O)(NEt(2))(tBu)}] 7 a' were prepared from the reaction of PhC[triple chemical bond]CP(NEt(2))(tBu) (5 a) with 2. The molecular structures of 7 a and 7 a' were determined by single-crystal X-ray diffraction. The phosphorus atom is surrounded by substituents in a tetrahedral environment. A P--N single bond (1.676(3) A) is observed in the molecular structure of 7 a. Heck reactions employing 7 a/Pd(OAc)(2) as catalyst system exhibited efficiency comparable to that of 8 a/Pd(OAc)(2).

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Palladium catalyzed Suzuki coupling reactions using cobalt-containing bulky phosphine ligands

Cited by 28 publications

References 24 publications

Synthesis of cobalt-containing monodentate phosphine ligand and application toward Suzuki cross-coupling reactions

Synthesis of cobalt-containing monodentate phosphine ligand and application toward Suzuki cross-coupling reactions

Suzuki cross‐coupling reaction of aryl and heterocyclic bromides and aromatic polybromides on a Pd(II)‐hydrotalcite catalyst

Experimental and DFT Study of the Tautomeric Behavior of Cobalt‐Containing Secondary Phosphine Oxides

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