Electrophilic Substitution Reactions of Metallabenzynes

Hung, WaiYiu; Liu, Bin; Shou, Wang-Ge; Wen, Ting Bin; Shi, Chuan; Sung, Herman H. Y.; Williams, Ian D.; Lin, Zhenyang; Jia, Guochen

doi:10.1021/ja207315h

Cited by 80 publications

(37 citation statements)

References 98 publications

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“…Although examples of these compounds are still relatively rare as well, the large possible number of variationsi nr ing size, heteroatom choice, degree of saturation and substitution (as well as possible isomers) suggests this could potentially developi nto av ery large set of compounds. Compounds in this class that have already been reported [117] include metallabenzothiirenes, [37,46,78] metallabenzoxirenes, [59,129] metallabenzazirines [59] metallabenzofurans, [91,[130][131][132][133][134] metallabenzothiophenes, [73,135] metallabenzothiazole, [52] metallabenzothiazolium, [78] and metallabenzoxathioles. [59,117] Formation of the ruthenabenzothiophene dimer 24,( am etalla-analogue of benzo[b]thiophene) was recently reportedt o occur via CÀHa ctivation of the thiophenes ubstituent of ac oordinated vinyl carbene ligand.…”

Section: Fused-ring Metallabenzenesmentioning

confidence: 99%

Recent Advances in Metallaaromatic Chemistry

Frogley

Wright

2017

Chemistry A European J

142

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Metallaaromatics can be broadly defined as aromatic compounds in which one of the ring atoms is a transition metal. The metallabenzenes are one important class of these compounds that has undergone extensive study recently. Closely related species such as fused-ring metallabenzenes, heterometallabenzenes, π-coordinated metallabenzenes and metallabenzynes have also attracted considerable attention. Although many metallaaromatics can be considered as metalla-analogues of classic organic aromatic compounds, this is not always the case. Recent seminal studies have shown that metallapentalenes and metallapentalynes, which are metalla-analogues of the anti-aromatic compounds pentalene and pentalyne, are in fact aromatic and highly stable. Very unusual spiro-metallaaromatic compounds have also recently been isolated. In this concepts article, key features of all these intriguing metallaaromatic compounds are discussed with reference to the structural, spectroscopic, reactivity and theoretical studies that have been undertaken. These compounds continue to generate much interest, not only because of the contributions they make to fundamental chemical understanding, but also because of the promise of possible practical applications.

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Section: Fused-ring Metallabenzenesmentioning

confidence: 99%

Recent Advances in Metallaaromatic Chemistry

Frogley

Wright

2017

Chemistry A European J

142

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“…We have demonstrated that a similar cyclic h 2 -allene complex, 2 ]Cl 2 , could isomerize to metallabenzene when CHCl 3 was employed as solvent in the reaction. [10c] By contrast, complex 4 is very stable in CHCl 3 under refluxing condition.…”

Section: Interconversion Of Metallabenzenes and Cyclic H 2 -Allene-comentioning

confidence: 99%

“…[1] Several approaches have been developed to construct a remarkable number of stable metallabenzene rings. [2] Common strategies previously employed are the formation of metallabenzenes from various unsaturated metallacycles, including four-, [3] five-, [4] and sixmembered metallacycles. [5] Reactivity studies of metallabenzenes demonstrated that the converse transformation could also be feasible.…”

Section: Introductionmentioning

confidence: 99%

Interconversion of Metallabenzenes and Cyclic η²‐Allene‐Coordinated Complexes

Lin

Zhao

Chen

et al. 2012

Chemistry An Asian Journal

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Treatment of the osmabenzene [Os{CHC(PPh(3))CHC(PPh(3))CH}Cl(2)(PPh(3))(2)]Cl (1) with excess 8-hydroxyquinoline produces monosubstituted osmabenzene [Os{CH C(PPh(3))CHC(PPh(3))CH}(C(9)H(6)NO)Cl(PPh(3))]Cl (2) or disubstituted osmabenzene [Os{CHC(PPh(3))CHC(PPh(3))CH}(C(9)H(6)NO)(2)]Cl (3) under different reaction conditions. Osmabenzene 2 evolves into cyclic η(2)-allene-coordinated complex [Os{CH=C(PPh(3))CH=(η(2)-C=CH(2))}(C(9)H(6)NO)(PPh(3))(2)]Cl (4) in the presence of excess PPh(3) and NaOH, presumably involving a P-C bond cleavage of the metallacycle. Reaction of 4 with excess 8-hydroxyquinoline under air affords the S(N) Ar product [(C(9)H(6)NO)Os{CHC(PPh(3))CHCHC}(C(9)H(6)NO)(PPh(3))]Cl (5). Complex 4 is fairly reactive to a nucleophile in the presence of acid, which could react with water to give carbonyl complex [Os{CH=C(PPh(3))CH=CH(2)}(C(9)H(6)NO)(CO)(PPh(3))(2)]Cl (6). Complex 4 also reacts with PPh(3) in the presence of acid and results in a transformation to [Os{CHC(PPh(3))CHCHC}(C(9)H(6)NO)Cl(PPh(3))(2)]Cl (7) and [Os{CH=C(PPh(3))CH=(η(2)-C=CH(PPh(3)))}(C(9)H(6)NO)Cl(PPh(3))]Cl (8). Further investigation shows that the ratio of 7 and 8 is highly dependent on the amount of the acid in the reaction.

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“…In comparison, benzyne ( II′ )11, 12 and isobenzene ( III′ )13 are too reactive and short‐lived to be isolated. Among the reactions of metallabenzynes,9e–h the interconversion of metallabenzyne and metallabenzene is particularly interesting9g, 14 because it resembles the mutual transformation of benzyne and benzene. On the other hand, isometallabenzenes remain rare,10 thus restricting the in‐depth studies of their chemistry.…”

Section: Introductionmentioning

confidence: 99%

Conversions of Osmabenzyne and Isoosmabenzene

Zhao

Zhu

Huang

et al. 2012

Chemistry A European J

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We report herein the first example of the conversion of metallabenzyne II and isometallabenzene III. The osmium hydride vinylidene complex 1 reacts with HC≡CCH(OEt)(2) to give osmabenzyne 3 via isoosmabenzene 2. Compound 3 exhibits high thermal stability in air. Nonetheless, nucleophilic attack at 3 provides isoosmabenzenes 4 a and 4 b, or opens the ring to produce 5 a and 5 b. We propose mechanisms to disclose the intrinsic connection between the six-membered metallacycles, and carry out DFT calculations to rationalize the regioselectivity of the nucleophilic addition reactions.

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Electrophilic Substitution Reactions of Metallabenzynes

Cited by 80 publications

References 98 publications

Recent Advances in Metallaaromatic Chemistry

Recent Advances in Metallaaromatic Chemistry

Interconversion of Metallabenzenes and Cyclic η²‐Allene‐Coordinated Complexes

Conversions of Osmabenzyne and Isoosmabenzene

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Electrophilic Substitution Reactions of Metallabenzynes

Cited by 80 publications

References 98 publications

Recent Advances in Metallaaromatic Chemistry

Recent Advances in Metallaaromatic Chemistry

Interconversion of Metallabenzenes and Cyclic η2‐Allene‐Coordinated Complexes

Conversions of Osmabenzyne and Isoosmabenzene

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Product

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Interconversion of Metallabenzenes and Cyclic η²‐Allene‐Coordinated Complexes