Nonclassical Bonding in Titanasilacyclohexadiene Compounds Resulting from Highly Methyl-Substituted Titanocene−Bis(trimethylsilyl)ethyne Complexes and Bis((trimethylsilyl)ethynyl)silanes

Horáček, Michal; Štěpnička, Petr; Gyepes, Róbert; Cı́sařová, Ivana; Kubišta, Jiřı́; Lukešová, Lenka; Meunier, and Philippe; Mach, Karel

doi:10.1021/om058038d

Cited by 21 publications

(7 citation statements)

References 38 publications

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“…Before closing this part, there is at least one example where ''non-classical'' bonding could be described C-C agostic. 48 The alkyne complexes (C 5 Me 5Àn H n ) 2 Ti(Z 2 -Me 3 SiCCSiMe 3 ) (n = 3, 4, 5) react with R 2 Si(CCSiMe 3 ) 2 (R = Me, Ph) to give 1-titana-4-sila-3,5bis(trimethylsilyl)cyclohexa-2,5-dienes 7 (Fig. 8).…”

Section: Main Group Early Transition Metals and Actinidesmentioning

confidence: 99%

Intramolecular C–C agostic complexes: C–C sigma interactions by another name

Étienne

Weller

2014

Chem. Soc. Rev.

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In this comprehensive review the developments in the synthesis, characterization and reactivity of complexes (s-, d- and f-block) in which a C-C single bond interacts with a metal centre are discussed: so called C-CM agostic complexes. Such species are of significant interest with regard to structure and bonding, the activation of C-C single bonds and, thus, catalytic methods of C-C bond formation (or activation). Examples of C-C agostic complexes of early and later transition metals, actinides and group 1 metals are discussed, along with C-C agostic interactions in metallacyclobutanes. Examples of Si-Si∙∙∙M, B-C∙∙∙M and B-B∙∙∙M agostic interactions are also presented. Throughout, the structural, spectroscopic and computational markers that indicate the likely presence of a C-C∙∙∙M agostic interaction in a complex are highlighted.

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Section: Main Group Early Transition Metals and Actinidesmentioning

confidence: 99%

Intramolecular C–C agostic complexes: C–C sigma interactions by another name

Étienne

Weller

2014

Chem. Soc. Rev.

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“…During our continued study on the zirconocene-mediated reaction of Si-tethered diynes, we realized that the metal-to-diyne ratio also played a key role in this case. − When the amount of the Si-tethered diyne l was increased from 1 to 2 equiv relative to Cp 2 ZrBu 2 , the 2,5-bis(alkynylsilyl)zirconacyclopentadiene 35 was isolated with high regio- and chemoselectivity (Scheme ). , Both aromatic and aliphatic substituents on the Si and the terminal alkynyl carbon atoms could be used. These results clearly showed that the metal-to-diyne ratio of “Cp 2 Zr” to Si-tethered diynes determined formation of either 2 or 35 .…”

Section: Reaction Of Complex 2 With Alkynes (Class Ii)mentioning

confidence: 99%

Zirconocene and Si-Tethered Diynes: A Happy Match Directed toward Organometallic Chemistry and Organic Synthesis

Zhang

2011

Acc. Chem. Res.

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Characterizing reactive organometallic intermediates is critical for understanding the mechanistic aspects of metal-mediated organic reactions. Moreover, the isolation of reactive organometallic intermediates can often result in the ability to design new synthetic methods. In this Account, we outline synthetic methods that we developed for a variety of diverse Zr/Si organo-bimetallic compounds and Si/N heteroatom-organic compounds through the detailed study of zirconacyclobutene-silacyclobutene fused compounds. Two basic components are involved in this chemistry. The first is the Si-tethered diyne, which owes its rich reactive palette to the combination of the Si-C bond and the C≡C triple bond. The second is the low-valent zirconocene species Cp(2)Zr(II), which has proven very useful in organic synthesis. The reaction of these two components affords the zirconacyclobutene-silacyclobutene fused compound, which is the key reactive Zr/Si organo-bimetallic intermediate discussed here. We discuss the three types of reactions that have been developed for the zirconacyclobutene-silacyclobutene fused intermediate. The reaction with nitriles (the C≡N triple bond) is introduced in the first section. In this one-pot reaction, up to four different components can be combined: the Si-tethered diyne can be reacted with three identical nitriles, with differing nitriles, or with a nitrile and other unsaturated organic substrates such as formamides, isocyanides, acid chlorides, aldehydes, carbodiimides, and azides. Several unexpected multiring, fused Zr/Si organo-bimetallic intermediates were isolated and characterized. A wide variety of N-heterocycles, such as 5-azaindole, pyrrole, and pyrroloazepine derivatives, were obtained. We then discuss the reaction with alkynes (the C≡C triple bond). A consecutive skeletal rearrangement, differing from that observed in the reactions with nitriles, takes place in this reaction. Finally, we discuss the reaction with the C═X substrates (where X is O or N), including ketones, aldehydes, and isocyanides. Oxa- and azazirconacycles are formed via a new skeletal rearrangement. Our results show that the zirconocene and the Si-tethered diyne cooperate as a "chemical transformer" after treatment with various substrates, leading to a diverse range of cyclic Zr/Si organo-bimetallic compounds. This mechanism-derived synthesis of organometallic and organic compounds demonstrates that the investigation of metal-mediated reactions and the isolation of reactive organometallic intermediates not only contribute to the understanding of complex reactions but can also lead to the discovery of synthetically useful methods.

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“…Horáček et al. reported the first titanium catalyst mediated synthesis of siloles . Equimolar amounts of 228 and 229 provided complex 230 in good yields (69‐84 %) when the mixture ( 228 + 229 ) was heated in xylene at 150 °C for 8 h (Scheme ).…”

Section: Synthetic Methodsmentioning

confidence: 99%

Synthesis and Application of Siloles: From the Past to Present

Santra

2020

ChemistrySelect

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Heterocyclic compounds in particular siloles in which a carbon atom has been replaced by an isovalent silicon atom, has gained wide attention recently. Due to their unique and interesting electronic and aggregation‐induced emmision properties, they found practical application in many areas. The properties of siloles depend upon the nature of subsituents present on the ring. Therefore, the synthetic methods and strategies continued to evolve since their first synthetic report. The advances in the synthesis of siloles, mechanistic details, substituents effect and applications have been discussed in this review.

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Nonclassical Bonding in Titanasilacyclohexadiene Compounds Resulting from Highly Methyl-Substituted Titanocene−Bis(trimethylsilyl)ethyne Complexes and Bis((trimethylsilyl)ethynyl)silanes

Cited by 21 publications

References 38 publications

Intramolecular C–C agostic complexes: C–C sigma interactions by another name

Intramolecular C–C agostic complexes: C–C sigma interactions by another name

Zirconocene and Si-Tethered Diynes: A Happy Match Directed toward Organometallic Chemistry and Organic Synthesis

Synthesis and Application of Siloles: From the Past to Present

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