Aryl Mesylates in Metal-Catalyzed Homocoupling and Cross-Coupling Reactions. 1. Functional Symmetrical Biaryls from Phenols via Nickel-Catalyzed Homocoupling of Their Mesylates

Percéc, Virgil; Bae, Jin‐Young; Zhao, Mingyang; Hill, Dale H.

doi:10.1021/jo00106a031

Cited by 143 publications

(80 citation statements)

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“…The yields for the hydrogen atom abstraction product (benzene) were determined to be 0.030%, 0.042% and 0.12% for 3 h at temperatures of 80, 100 and 120°C, respectively. Negligible hydrogen atom abstraction has also been reported in other palladium catalyzed coupling reactions [37][38][39][40]. These results suggest that the biphenyl formation proceeds via the concerted mechanism rather than the stepwise mechanism through the aryl radical intermediate, followed by radical dimerization [13,41], since the hydrogen atom abstraction of aryl radicals from solvent DMSO is diffusion-controlled (1 Â 10 8 M À1 s À1 ) [42].…”

Section: Resultssupporting

confidence: 54%

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Sun

et al. 2009

Journal of Organometallic Chemistry

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Section: Resultssupporting

confidence: 54%

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Sun

et al. 2009

Journal of Organometallic Chemistry

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“…These results give evidence for the electrophilic character of the nickel center, which is consistent with the previous studies of C-H bond activation of nickel center in solution [63][64][65].…”

Section: Fragmentation Of [Arni(pph 3 ) 2 ]supporting

confidence: 92%

Studies on gas-phase cyclometalations of [ArNi(PPh₃)n]⁺ (n = 1 or 2) by electrospray ionization tandem mass spectrometry

Zhou

Zhao

Chen

et al. 2010

J. Am. Soc. Mass Spectrom.

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Gas-phase cyclometalation of [ArNi(PPh 3 ) n ] ϩ (n ϭ 1, 2) complexes have been studied by ESI-MS/MS. The electron-donating substituents of aromatic iodides in the para position were found to inhibit the cyclometalation process of losing ArH, while the electron-withdrawing substituents in the para position were found to enhance it. These results indicate that the cyclometalation process of losing ArH is favored by electron-deficient aromatic groups. In addition, the detailed dissociation pathways of the cationic nickel complexes were studied, and among these pathways, the process of aryl-aryl interchange was also found to proceed in ESI-MS/MS. (J Am Soc Mass Spectrom 2010, 21, 1265-1274) © 2010 American Society for Mass Spectrometry C yclometalation occurs when a ligand on an organo-metal complex undergoes an intramolecular metalation with concomitant formation of a chelate ring containing a metal-carbon bond [1]. This kind of transformation has attracted significant attention over the past three decades [2][3][4][5][6][7]. On the one hand, cyclometalation can be detrimental to a desired reaction course and can be prevented by a variety of techniques to improve catalytic efficiency of the metal complex. As cyclometalation methodology has been developed, a number of cyclometalated complexes were employed successfully in organic synthesis [8,9], catalysis [10 -12], and photochemistry [13][14][15]. Mechanisms for the cyclometalation associated with C-H bond cleavage have been proposed [16 -21], and three related mechanisms for C-H bond cleavage are typically accepted: oxidative addition, electrophilic substitution, and multicentered pathways (such as -bond metathesis) [22][23][24][25][26]. The actual mechanisms that pertain for cyclometalation of a given metal complex are highly dependent on the exact nature of the metal complexes, identities of hydrocarbon substituents, solvents involved, and specific operating conditions [21]. As a result, a complete understanding and description of the general mechanism are still lacking, and more data are needed before we can fully describe critical reactivity patterns.The focus to date has been on the study of solutionphase cyclometalations, but gas-phase cyclometalations have recently received more attention [27][28][29]. Generally, gas-phase studies conducted with tandem mass spectrometry (MS/MS) on extremely small sample quantities can theoretically ascertain the propensity for a complex to undergo certain kinds of reactions. The energy conditions and dissociation pathways provide useful insights, with applicability to related solutionphase reactions [30 -40]. Based on the gas-phase methodologies, Henderson and coworkers published their investigation of the cyclometalation of palladium(II) and platinum(II) diphosphine complexes MCl 2 (Ph 2 P (CH 2 ) 5 PPh 2 ) in 2004 [28]. More recently, Schwarz and coworkers explored the whole process of cyclometalation of 2,2=-bipyridine platinum(II) complexes in gas phase by a combination of gas-phase methodologies and theoretical calcu...

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“…For example, Kumada coupling reactions use magnesium for the formation of active alkyl/ aryl magnesium bromide species (Grignard formation), which is generally a substrate-and solvent-specific reaction (working optimally in tetrahydrofuran or diethyl ether as solvents). [6][7][8][9][10] Nickel reactions facilitated by the addition of zinc powder have been utilized in a similar fashion in organic synthesis, [11][12][13] as well as in efficient condensation polymerizations. [14][15][16] These reactions are not always well controlled, require prolonged heating at high temperatures, and the products have high levels of metal impurities that can be difficult and costly to remove.…”

mentioning

confidence: 99%

“…Bpy (18 mg, 115.24 mmol) was added to the reaction solution as a ligand and was found to be necessary for the coupling reaction to proceed in higher yields. [11] Commercially available nBuLi, secBuLi, and tBuLi solutions were used for the reactions. Alkyllithium was added at half molar equivalents to that of phenyl bromide groups with the intention of generating an equimolar ratio of lithiated benzene anions to unreacted phenyl bromide groups.…”

mentioning

confidence: 99%

Nickel‐Catalyzed Coupling of Aryl Bromides in the Presence of Alkyllithium Reagents

Jhaveri¹,

Carter²

2008

Chemistry A European J

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Transition-metal-catalyzed coupling reactions of halogenated molecules leading to formation of new carbon-carbon bonds are a very important category of reactions used in the synthesis of complex compounds and conjugated polymers. [1][2][3] Within the past decade, this methodology has evolved into a powerful synthetic tool for the preparation of a wide range of specialty polymers, composite materials, and pharmaceutically active compounds both in the laboratory and on the industrial scale. It is also widely appreciated in the context of parallel synthesis and combinational chemistry. [4,5] We desired to develop an improved catalytic method for transition-metal-catalyzed aryl coupling reactions and report herein the one-pot, one-step, nickel-catalyzed coupling of aryl bromides in the presence of alkyllithium reagents [Eq. (1)].Metallic reagents including palladium and nickel complexes have demonstrated to be quite effective in C À C coupling reactions. Typically, coupling reactions of aryl halides involving the use of catalytic amounts of nickel(II) complexes require the addition of either magnesium or zinc to facilitate efficient coupling and regeneration of active nickel(0) catalytic species. For example, Kumada coupling reactions use magnesium for the formation of active alkyl/ aryl magnesium bromide species (Grignard formation), which is generally a substrate-and solvent-specific reaction (working optimally in tetrahydrofuran or diethyl ether as solvents). [6][7][8][9][10] Nickel reactions facilitated by the addition of zinc powder have been utilized in a similar fashion in organic synthesis, [11][12][13] as well as in efficient condensation polymerizations. [14][15][16] These reactions are not always well controlled, require prolonged heating at high temperatures, and the products have high levels of metal impurities that can be difficult and costly to remove. This trace-metal contamination is especially problematic if the end use is in pharmaceutical or microelectronic applications in which safety, performance, and reliability require stringent control of purity. Another known aryl-halide coupling reaction involves the use of highly reactive zinc (Rieke zinc), which is prepared by reduction of ZnCl 2 with lithium naphthalenide and has been shown to readily undergo oxidative addition with alkyl, aryl, and vinyl halides under mild conditions to generate the corresponding organozinc compounds. These reactive organozinc compounds are then cross-coupled with other aryl or vinyl halides using palladium(0) catalysts. [17] Recently, homocoupling of bromide compounds has been facilitated through the combination of metallic magnesium and a catalytic amount of iron salts.[18] Coupling reactions involving activated dihalogenated thiophene molecules catalyzed by nickel(II) complexes have also been demonstrated in the presence of reactive zinc (Rieke zinc) [19] or an alkylmagnesium reagent (GRIM/McCullough method) [20] to form regioregular polythiophenes.Coupling reactions of halogenated molecules involving nickel(0) compl...

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Aryl Mesylates in Metal-Catalyzed Homocoupling and Cross-Coupling Reactions. 1. Functional Symmetrical Biaryls from Phenols via Nickel-Catalyzed Homocoupling of Their Mesylates

Cited by 143 publications

References 0 publications

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Studies on gas-phase cyclometalations of [ArNi(PPh₃)n]⁺ (n = 1 or 2) by electrospray ionization tandem mass spectrometry

Nickel‐Catalyzed Coupling of Aryl Bromides in the Presence of Alkyllithium Reagents

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Aryl Mesylates in Metal-Catalyzed Homocoupling and Cross-Coupling Reactions. 1. Functional Symmetrical Biaryls from Phenols via Nickel-Catalyzed Homocoupling of Their Mesylates

Cited by 143 publications

References 0 publications

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Palladium catalyzed reductive homocoupling reactions of aromatic halides in dimethyl sulfoxide (DMSO) solution

Studies on gas-phase cyclometalations of [ArNi(PPh3)n]+ (n = 1 or 2) by electrospray ionization tandem mass spectrometry

Nickel‐Catalyzed Coupling of Aryl Bromides in the Presence of Alkyllithium Reagents

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Studies on gas-phase cyclometalations of [ArNi(PPh₃)n]⁺ (n = 1 or 2) by electrospray ionization tandem mass spectrometry