Chemistry of organosilicon compounds. 263. Synthesis, properties, and molecular structure of highly distorted hexakis(trimethylsilyl)benzene

Sakurai, Hideki; Ebata, Keisuke; Kabuto, Chizuko; Sekiguchi, Akira

doi:10.1021/ja00161a023

Cited by 79 publications

(38 citation statements)

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“…[3] This tether can induce the maximum bending angle of 24.98 as in [1.1]paracyclophane [3b] (Figure 1 a). Another approach involves the introduction of bulky substituents on the benzene rings of acene [4] to avoid steric repulsion, thus neighboring substituents favor the twisting of the benzene rings. The twist and bending angles for each benzene ring are in the range of 27 to 308 and 19 to 228, respectively (Figure 1 b).…”

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Construction of a Highly Distorted Benzene Ring in a Double Helicene

et al. 2014

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A P-fused double helicene consisting of a highly distorted benzene ring, with a bending angle of 23°, has been synthesized by a tandem intramolecular phospha-Friedel-Crafts reaction. Despite the distortion and reduced aromaticity, the double helicene shows thermal and chemical stability. These are important features that make these compounds attractive for applications as a new C2-symmetric bisphosphine ligand. The simple strategy proposed in this work can be used to prepare a diverse range of distorted molecules.

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Construction of a Highly Distorted Benzene Ring in a Double Helicene

et al. 2014

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“…[27] The target compound, hexakis(trimethylsilyl)benzene, has already been described by Sakurai et al, who started from hexabromobenzene and developed a three-step synthesis sequence via hexakis-A C H T U N G T R E N N U N G (dimethylsilyl)benzene. [28] Previous attempts of Gilman et al at the direct trimethylsilylation of hexabromobenzene (Mg/Me 3 SiCl/THF, reflux, 12 h) have failed. [29,30] The only well-defined product that could be isolated in small amounts from the reaction mixtures, was 1,1,3,4,6,6-hexakis(trimethylsilyl)-1,2,4,5-hexatetraene (3; Scheme 2).…”

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confidence: 99%

“…[29,30] The only well-defined product that could be isolated in small amounts from the reaction mixtures, was 1,1,3,4,6,6-hexakis(trimethylsilyl)-1,2,4,5-hexatetraene (3; Scheme 2). [29,30] Since hexakis(trimethylsilyl)benzene is known to undergo a rearrangement reaction to afford 3 upon thermal treatment, [28] we reckoned that the lower reaction temperature required for the Rieke-Mg protocols might offer an opportunity to prepare hexakis(trimethylsilyl)benzene in one step. However, the reaction with Mg R took a similar course as the Gilman experiments and 3 was obtained as one of several products (Scheme 2).…”

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confidence: 99%

Improved Synthesis of 1,2‐Bis(trimethylsilyl)benzenes using Rieke‐Magnesium or the Entrainment Method

Lorbach¹,

Reus²,

Bolte³

et al. 2010

Adv Synth Catal

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1,2-Bis(trimethylsilyl)benzene is the key starting material for the synthesis of efficient benzyne precursors and certain luminescent p-conjugated materials. We now report that it can be conveniently prepared in tetrahydrofuran from 1,2-dibromobenzene, chlorotrimethylsilane, and either Rieke-magnesium (Mg R ) or magnesium turnings in the presence of 1,2-dibromoethane as an entrainer (Mg e ). The most important advantages of these new protocols over the currently best-established procedure (1,2-dichlorobenzene, chlorotrimethylsilane, magnesium turnings, hexamethylphosphoramide) lie in the milder reaction conditions (Mg R : 08C, 2 h; Mg e : room temperature, 30 min vs. 100 8C, 2 days) and in the fact that the cancerogenic solvent hexa-A C H T U N G T R E N N U N G methylphosphoramide is avoided. Moreover, the improved protocols are also applicable for the highyield synthesis of 1,2,4,5-tetrakis(trimethylsilyl)benzene, 4-fluoro-1,2-bis(trimethylsilyl)benzene, 4-chloro-1,2-bis(trimethylsilyl)benzene, and 4,5-dichloro-1,2-bis(trimethylsilyl)benzene.

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“…[5] Encouraged by the preparation of a dialkynyl derivative, [5b] we envisioned the preparation of the hexaalkynyl carbobenzene 1 a, which is a protected version of the total carbomer 1 b and was studied recently at the level of density functional theory (DFT; Scheme 1). [6] The target 1 a is also a skeletal carbomer of hexa(trialkylsilyl)benzenes, such as 1 a' [7] and 1 a''. [8] Our experience in the synthesis of n-oxy[n]pericyclynes (n = 5, 6) [9] led us to tackle the proposed challenge through the "classical" strategy based on the reductive aromatization of the corresponding hexaoxy [6]pericyclynes 2 a,b (Scheme 1).…”

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confidence: 99%