Interaction of the five-membered zirconacyclocumulene complex Cp2Zr(η4-tBuC4tBu) with acetylenes. Synthesis of zirconacyclopentadienes and seven-membered zirconacyclocumulenes

Burlakov, Vladimir V.; Bogdanov, V. S.; Arndt, Perdita; Spannenberg, Anke; Lyssenko, Konstantin А.; Baumann, Wolfgang; Minacheva, M. Kh.; Strunin, B.N.; Rosenthal, Uwe; Shur, V. B.

doi:10.1016/j.jorganchem.2013.07.026

Cited by 17 publications

(19 citation statements)

References 26 publications

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“…In the course of further investigations, differently substituted five‐membered cyclocumulenes of group 4 metallocenes (M = Ti, Zr, Hf) were synthesized. It was observed that zirconacyclocumulenes undergo a slow transformation to seven‐membered metallacyclocumulenes 15,16…”

Section: Resultsmentioning

confidence: 99%

“…Recently detailed investigations by NMR spectroscopy16 revealed that, on heating (100 °C) in solution, zirconacyclocumulene 1 eliminates one butadiyne molecule, and an equilibrium between the corresponding five‐membered cyclocumulene ( II , Scheme ) and a zirconacyclopropene ( I , Scheme ) structure exists in the reaction mixture, in which I is likely to be the reactive species. This alkyne complex afforded insertion and C–C coupling of one MeC≡N molecule with the coordinated acetylene molecule.…”

Section: Resultsmentioning

confidence: 99%

“…Prior to use, n ‐hexane and toluene were distilled from sodium tetraethylaluminate and stored under argon. Zirconacyclocumulene complex 1 was prepared according to a literature procedure 15,16. The following spectrometers were used: NMR spectra: Bruker AV400 and AV300.…”

Section: Methodsmentioning

confidence: 99%

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Reactivity of a Seven‐Membered Zirconacyclocumulene towards CN Multiple Bonds – Formation of Metallaheterocycles by Insertion of C≡N and C=N Groups

et al. 2014

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The reactions of the seven-membered zirconacyclocumulene [Cp 2 Zr{η 4 -Me 3 SiC 4 (SiMe 3 )-C(C 2 SiMe 3 )=CSiMe 3 }] (1) with nitriles (RCϵN, R = Me, Ph) started with an insertion of a cyanide group into the metal-butadiyne bond followed by an alkyne-nitrile coupling and formation of 1-zircona-2-azacyclopenta-2,4-dienes. The reaction product for R = Me is stabilized by dimerization to give a compound containing a four-membered -N-Zr-N-Zr-ring and two identical fivemembered 1-metalla-2-aza-cyclopentadiene rings. In case of R = Ph, a metallacycle could not be isolated, and a pyrimidine[a] Leibniz-5304 was formed. The catalytic potential of this reaction was investigated. For PhN=C(H)Ph, again after insertion and coupling, a corresponding 1-zircona-2-azacyclopenta-4-ene was established. The reaction of this compound with carbon dioxide led to ring expansion and formation of a seven-membered product, which released CO 2 at higher temperature and to give back the reactant. The above-mentioned products were characterized by NMR spectroscopy and singlecrystal X-ray structure analysis.ing from these alkyne complexes, five-membered, all-carbon metallacycles, such as 1-metallacyclopenta-2,4-dienes (metallacyclopentadienes A, Scheme 1), 1-metallacyclopent-3-ynes (metallacyclopentynes B, Scheme 1), and 1metallacyclopenta-2,3,4-trienes (metallacyclocumulenes C, Scheme 1), were synthesized to study their reaction behavior. [2,3] In many cases, coupling reactions of two alkynes were observed to yield 1-metallacyclopenta-2,4-dienes A. [5] We were now interested in the formation of the analogous heterocycles by the coupling of nitriles. The corresponding 1-metalla-2,5-diazacyclopenta-2,4-dienes D (Scheme 1), which result from a nitrile-nitrile coupling, are very rare. [6] Lately, these metallacycles were synthesized by reaction of arylnitriles with [Cp* 2 M(η 2 -Me 3 SiC 2 SiMe 3 )] (M = Ti, Zr; Cp* = η 5 -pentamethylcyclopentadienyl). [7] Additionally, there were hints for the formation of the corresponding five-membered 1-metalla-2-aza-cyclopenta-2,4-dienes E (Scheme 1), established by an alkyne-nitrile C-C coupling, which were assumed as intermediates in the synthesis of heteroaromatic compounds. [8] To the best of our knowledge, only in the case of 3-ferrocenyl-2-propyne-nitrile and zirconocene [7b] and for an aluminum complex [6a] has the corresponding metallacyclopentadiene E been isolated by alkyne-nitrile coupling.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Reactivity of a Seven‐Membered Zirconacyclocumulene towards CN Multiple Bonds – Formation of Metallaheterocycles by Insertion of C≡N and C=N Groups

et al. 2014

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“…[12,13] Moreover, attempts to prepare β-silyl phospholes by using the Fagan-Nugent method starting from silylalkynes failed in our hands, which may be attributed to the reversible interaction of silylalkynes with certain transition-metal centers. [14,15] We became intrigued by a synthetic approach to phospholes discovered by Märkl et al employing formal hydrophosphination of suitable diynes by using phenyllithium as catalyst. [16] Recently, the scope of this reaction has been nicely extended.…”

Section: Introductionmentioning

confidence: 99%

A Rational Synthetic Approach to 2,5‐Diphenyl‐β‐silyl Phospholes

et al. 2015

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Systematic access to β-silyl-substituted phospholes is reported. The synthesis proceeds through the addition of lithium phosphanide to a diyne and silylation of the intermediate β-lithio phosphole. By following this approach, mono and disilylation has been accomplished and the reactivity of the β-silyl phospholes towards oxidation with chalcogens and conversion into phospholides has been explored. The silyl units have

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“…Since the pioneered works of Buchwald’s, Burlakov and Rosenthal, − the two types of metallacycles containing [3]cumulene fragments 1 an 2 are known for group 4 metallocenes (Figure ). ,− They have not only high stability but also unique chemical behavior and electronic structure. The group 4 metal atom incorporation leads to excited mesomerism/valence tautomerism in unsaturated metallacycles and new synthetic routes of other synthetically used systems. − …”

Section: Introductionmentioning

confidence: 99%

Aromaticity of 5- and 7-Membered Metallacyclocumulenes of Group 4

Aysin

Bukalov

2021

Organometallics

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Using the recent aromatic criteria, the conjugation and aromatic properties of group 4 metallacyclocumulenes Cp 2 M-η 4 −(R)CCCC−R (1) and Cp 2 M-η 3 (R−C CCC(R)−R(C) CR) (2) (M = Ti, Zr, Hf) were studied. To these nontrivial bonded metallacycles, the most recent universal criteria of aromaticity were applied that do not require any parametrisation such as isomerisation stabilization energy, electron density of delocalized bonds (EDDB), nuclear independent chemical shift, and gauge-included magnetically induced currents (GIMIC). All methods used indicated the absence of the common π-type aromaticity. The most efficient EDDB and GIMIC methods showed in-plane aromatic pathway in 5-membered cycle 1 against 7-membered 2. The distribution of the induced currents (ICs) for such unique aromaticity type was demonstrated. It shows that the diatropic ICs of 1 are located both inside and outside the cycle. The population analysis of molecular orbitals and natural orbitals for delocalized bonds revealed the abidance to the 4n + 2 electron rule. According to EDDB and GIMIC data, the degree of aromaticity for 1 tends to decrease from Ti to Zr and Hf. Article pubs.acs.org/Organometallics

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Interaction of the five-membered zirconacyclocumulene complex Cp2Zr(η4-tBuC4tBu) with acetylenes. Synthesis of zirconacyclopentadienes and seven-membered zirconacyclocumulenes

Cited by 17 publications

References 26 publications

Reactivity of a Seven‐Membered Zirconacyclocumulene towards CN Multiple Bonds – Formation of Metallaheterocycles by Insertion of C≡N and C=N Groups

Reactivity of a Seven‐Membered Zirconacyclocumulene towards CN Multiple Bonds – Formation of Metallaheterocycles by Insertion of C≡N and C=N Groups

A Rational Synthetic Approach to 2,5‐Diphenyl‐β‐silyl Phospholes

Aromaticity of 5- and 7-Membered Metallacyclocumulenes of Group 4

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