Pentalenes with novel topologies: exploiting the cascade carbopalladation reaction between alkynes and gem-dibromoolefins

London, Gábor; Rekowski, Margarete von Wantoch; Dumele, Oliver; Schweizer, W. Bernd; Gisselbrecht, Jean‐Paul; Boudon, Corinne; Diederich, François

doi:10.1039/c3sc52623b

Cited by 62 publications

(64 citation statements)

References 58 publications

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“…In recent years, dibenzopentalene derivatives have attracted considerable attentions because of their unique planar structures, antiaromatic characters and promising application in organic materials science 20,21 . Several reliable methods for the synthesis of dibenzopentalene derivatives were designed and reported [22][23][24][25][26][27][28][29][30] . In case of dinaphthopentalene derivatives, Kawase et al 31 reported the unique synthesis and application in organic thinfilm transistors.…”

Section: Resultsmentioning

confidence: 99%

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Wang

Wei

et al. 2014

Nat Commun

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Organomagnesium compounds (Grignard reagents) are among the most useful organometallic reagents and have greatly accelerated the advancement of synthetic chemistry and related sciences. Nevertheless, heavy Grignard reagents based on the metals calcium, strontium or barium are not widely used, mainly due to their rather inert heavy alkaline-earth metals and extremely high reactivity of their corresponding Grignard-type reagents. Here we report the generation and reaction chemistry of butadienyl heavy Grignard reagents whose extremely high reactivity is successfully tamed. Facile synthesis of perfluoro-π-extended pentalene and naphthalene derivatives is realized by the in situ generated heavy Grignard reagents via intramolecular C-F/C-H bond cleavage. These obtained perfluorodibenzopentalene and perfluorodinaphthopentalene derivatives show low-lying LUMO levels, with one being the lowest value so far among all pentalene derivatives. Our results set an exciting example for the meaningful synthetic application of heavy Grignard reagents.

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Section: Resultsmentioning

confidence: 99%

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Wang

Wei

et al. 2014

Nat Commun

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“…Thus, whereas [ a , e ]DBP is a closed‐shell species consisting of the weakly paratropic pentalene core and two benzenes with attenuated aromaticity, the isomeric [ a , f ]DBP has an open‐shell character with a small energy difference between the singlet and triplet states as well as an enhanced global paratropicity . An attempt to prepare the additionally benzene‐fused [ a , f ]DBP , dinaphtho[1,2‐ a :2,1‐ f ]pentalene (Figure ) failed, but its structural isomer, dinaphtho[2,1‐ a :1,2‐ f ]pentalene, and the related benzo[ a ]naphtho[1,2‐ f ]pentalene (Figure ) have recently been synthesized and characterized as closed‐shell species in which the global paratropicity of [ a , f ]DBP is mainly shifted to the pentalene core …”

Section: Introductionmentioning

confidence: 99%

A DFT Study of the Modulation of the Antiaromatic and Open‐Shell Character of Dibenzo[a,f]pentalene by Employing Three Strategies: Additional Benzoannulation, BN/CC Isosterism, and Substitution

Baranac‐Stojanović

2019

Chemistry A European J

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Dibenzo[a,f]pentalene ([a,f]DBP) is a highly antiaromatic molecule having appreciable open‐shell singlet character in its ground state. In this work, DFT calculations at the B3LYP/6‐311+G(d,p) level of theory were performed to explore the efficiency of three strategies, that is, BN/CC isosterism, substitution, and (di)benzoannulation of [a,f]DBP, in controlling its electronic state and (anti)aromaticity. To evaluate the type and extent of the latter, the harmonic oscillator model of aromaticity (HOMA) and aromatic fluctuation (FLU) indices were used, along with the nucleus‐independent chemical shift NICS‐XY‐scan procedure. The results suggest that all three strategies could be employed to produce either the closed‐shell system or open‐shell species, which may be in the singlet or triplet ground state. Triplet states have been characterized as aromatic, which is in accordance with Baird's rule. All the singlet states were found to have weaker global paratropicity than [a,f]DBP. Additional (di)benzo fusion adds local aromatic subunit(s) and mainly retains the topology of the paratropic ring currents of the basic molecule. The substitution of two carbon atoms by the isoelectronic BN pair, or the introduction of substituents, results either in the same type and very similar topology of ring currents as in the parent compound, or leads to (anti)aromatic and nonaromatic subunits. The triplet states of all the examined compounds are also discussed.

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“…Pentalene as well as the structurally similar indenofluorene [1] is one of the important core structures for materials cience. [3] The properties of pentalene are of high interest for organic semiconductors. [3] The properties of pentalene are of high interest for organic semiconductors.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the low stability of the pure pentalene core, [2] various syntheses of dibenzo[a,e]-pentalenes,w hich are stabilized by the fused aromatic moieties, have been developed. [3] The properties of pentalene are of high interest for organic semiconductors. Especially, p-extended pentalenesp rove to act as p-or n-type organic transistors, although tuning optoelectronicp roperties by the introduction of functionalg roups are still desirable for higher performance.…”

Section: Introductionmentioning

confidence: 99%

Gold‐Catalyzed Regiospecific Annulation of Unsymmetrically Substituted 1,5‐Diynes for the Precise Synthesis of Bispentalenes

Tavakkolifard

Sekine

Reichert

et al. 2019

Chemistry A European J

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Precisec ontrol of the selectivity in organic synthesis is importantt oa ccess the desired molecules. We demonstrate ar egiospecific annulation of unsymmetrically substituted 1,2-di(arylethynyl)benzened erivatives for ag eometrycontrolled synthesis of linear bispentalenes, which is one of the promisings tructures for materials cience.Ag old-catalyzed annulation of unsymmetrically substituted 1,2-di(arylethynyl)benzene could produce two isomeric pentalenes, but both electronic and steric effectso nt he aromatics at the terminal position of the alkyne prove to be crucial for the selectivity;e speciallyaregiospecific annulationw as achieved with sterically blockeds ubstituents;n amely,2 ,4,6-trimetylb enzene or 2,4-dimethyl benzene. This approache nables the geometrically controlled synthesis of linear bispentalenes from 1,2,4,5-tetraethynylbenzeneo r2 ,3,6,7-tetraethynylnaphthalene. Moreover,t he annulation of as eries of tetraynesw ith ad ifferent substitution pattern regioselectively provided the bispentalene scaffolds.Ac omputational study revealed that this is the result of ak inetic control induced by the bulky NHC ligands.

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Pentalenes with novel topologies: exploiting the cascade carbopalladation reaction between alkynes and gem-dibromoolefins

Cited by 62 publications

References 58 publications

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

Intramolecular C–F and C–H bond cleavage promoted by butadienyl heavy Grignard reagents

A DFT Study of the Modulation of the Antiaromatic and Open‐Shell Character of Dibenzo[a,f]pentalene by Employing Three Strategies: Additional Benzoannulation, BN/CC Isosterism, and Substitution

Gold‐Catalyzed Regiospecific Annulation of Unsymmetrically Substituted 1,5‐Diynes for the Precise Synthesis of Bispentalenes

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