Lithium-induced cyclization of tribenzocyclyne: synthesis and structural characterization of a novel helicene dianion, its protonated form, silylated isomers of a substituted fulvalene ligand, and a novel dimeric lithium complex

Malaba, Dennis; Djebli, Abdellah; Chen, Lee; Zarate, Eugene A.; Tessier, Claire A.; Youngs, Wiley J.

doi:10.1021/om00028a049

Cited by 45 publications

(23 citation statements)

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“…Such transformation can be achieved by either electrophilic [18], nucleophilic [19], or reductive [20] pathway. For example, attack of an electrophile to the triple bond, transannular bond formation, and capture of the vinylic cation intermediate by a nucleophile would give a zethrene derivative as shown in Scheme 2.…”

Section: 14-disubstituted Zethrene Derivativesmentioning

confidence: 99%

Tetradehydrodinaphtho[10]annulene and its transformation into zethrene: A hitherto unknown dehydroannulene and a forgotten aromatic hydrocarbon

Umeda

Hibi

Miki

et al. 2010

Pure and Applied Chemistry

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The synthesis and structural characterization of a hitherto unknown tetradehydrodinaphtho[10]annulene, which had eluded isolation since attempts initiated during the late 1960s, was achieved. Moreover, the dehydroannulene was transformed into stable derivatives of zethrene, which was first reported in 1955, but forgotten for a long time. These molecules are substituted at the 7,14-positions and open the door to the zethrene family for potential application as optoelectronic materials.

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Section: 14-disubstituted Zethrene Derivativesmentioning

confidence: 99%

Tetradehydrodinaphtho[10]annulene and its transformation into zethrene: A hitherto unknown dehydroannulene and a forgotten aromatic hydrocarbon

Umeda

Hibi

Miki

et al. 2010

Pure and Applied Chemistry

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“…Moreover, cyclic precursors would limit the number of possible reaction pathways because of steric constraints. Indeed, a few examples of efficient transformations of dehydrobenzannulenes into polycyclic carbon frameworks were reported as exemplified for octadehydrodibenzo [12]annulene, [2] hexadehydrotribenzo [12]annulene, [3] and tetradehydrodibenzo [8]annulene. [4] The reactions are typically induced by attack of a nucleophile, [4a] an electrophile, [2, 4b] or a radical, [3c] or initiated by reduction to generate a radical anion.…”

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confidence: 99%

Oxidative Cyclodimerization After Tandem Cyclization of Dehydrobenzo[14]annulenes Induced by Alkyllithium

et al. 2013

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Highly ethynylated compounds have the potential to be transformed into polycyclic aromatic hydrocarbons by intramolecular cyclizations between the sp-carbon atoms because of the high reactivity of carbon-carbon triple bonds. [1] Particularly those with cyclic structures are useful for the construction of new carbon frameworks which are otherwise difficult to obtain. Moreover, cyclic precursors would limit the number of possible reaction pathways because of steric constraints. Indeed, a few examples of efficient transformations of dehydrobenzannulenes into polycyclic carbon frameworks were reported as exemplified for octadehydrodibenzo [12]annulene, [2] hexadehydrotribenzo [12]annulene, [3] and tetradehydrodibenzo [8]annulene.[4] The reactions are typically induced by attack of a nucleophile, [4a] an electrophile, [2, 4b] or a radical, [3c] or initiated by reduction to generate a radical anion. [3a,b] We envisaged that octadehydrotribenzo [14]annulene ([14]DBA) 1 a [5] and its congeners 2-4 would serve as intriguing substrates for multiple trasnannular bond formations to yield new polycyclic frameworks because of the presence of four closely located triple bonds. Additionally, the distorted butadiyne unit is expected to trigger reactions induced by an electrophile [2a] or a nucleophile, [4a] which would not occur for unactivated acetylenic bonds. [4a, 6] We report herein the results of the reactions of 1 and its congeners, 2-4, with butyllithium (nBuLi). We discovered an unprecedented oxidative cyclodimerization to form eight-membered ring products, in which two indeno[2,1-a]fluorene components are connected by a single and a double bond, following three transannular CÀC bond formations.First we envisioned the possible pathways for the tandem transannular cyclizations of 1 a as shown in Scheme 1. In the initial step, we assume the formation of a five-membered ring after the addition of a nucleophile to the diyne moiety of 1 a to give the intermediate 7 on the basis of the previous reports. [2a, 3, 4a] For the second step, there are two options of transannular bond formation: 1) formation of a four-membered ring to give 9 or 2) a five-membered ring to form the 5/ 8/5 ring system 8. In the former case, the resulting ninemembered ring can be further divided into 5/6 a ring system to afford the tetracyclic intermediate 11 bearing an indeno[2,1-a]fluorene substructure, or the 4/7 system 10 possessing two benzocyclobutene units. As to the indeno[2,1-a]fluorene framework, while Le Berre et al. reported the synthesis of the unstable 11,12-diphenylderivatives 5 a, [7] we succeeded recently in the synthesis of the robust dimesityl-substituted derivative 5 b and clarified its physical properties including its singlet diradical character.[8] These results suggest that the expected product 12, formed by interception of 11 with an electrophile, must be substantially reactive.When the di-tert-butyl[14]DBA 1 b was treated with nBuLi at À78 8C in THF and subsequently quenched with water or 1-iodobutane at the same tem...

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“…[11] The [12]DBA skeleton was however found to be unstable to a second reduction if the reduction was performed chemically. [58] Further studies have since been reported for [12]DBAs functionalized with CN, F, and COOMe acceptor, and NR 2 and OMe donor groups, [42,47] and [12]DBAs variously functionalized with ethynyl substituents. [13,59] In accordance with the conclusions from theoretical studies, [42] acceptor substituents facilitate reduction of the [12]DBA ring system relative to 1, while donor functionality enables oxidation processes to occur.…”

Section: Electrochemical Study Ofmentioning

confidence: 99%

A Direct One‐Pot Synthesis of Asymmetric Dehydrobenzopyrido[12]annulenes and Their Physicochemical Properties

et al. 2017

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A direct one‐pot synthesis of asymmetric dehydrobenzopyrido[12]annulenes 2 and 3 containing one or two pyridine rings is reported that employs a Stephens–Castro mediated cross‐coupling of mixtures of ethynylcuprate precursors. The spectroscopic and theoretical properties of 2 and 3 are compared to those of the threefold symmetric dehydrotribenzo[12]annulene 1, and dehydrotripyrido[12]annulenes 4 and 5 and dehydrodibenzodipyrido[16]annulene byproduct 6, and showed 1–5 to be essentially isoelectronic band gap materials whose electron accepting ability increases with increasing nitrogen incorporation. The structures of 2, 4 and 6 were also unambiguously characterized by X‐ray crystallography. The results highlight the potential dehydroaryl[12]annulenes incorporating pyridines offer for the construction of high carbon content electronic materials.

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Lithium-induced cyclization of tribenzocyclyne: synthesis and structural characterization of a novel helicene dianion, its protonated form, silylated isomers of a substituted fulvalene ligand, and a novel dimeric lithium complex

Cited by 45 publications

References 1 publication

Tetradehydrodinaphtho[10]annulene and its transformation into zethrene: A hitherto unknown dehydroannulene and a forgotten aromatic hydrocarbon

Tetradehydrodinaphtho[10]annulene and its transformation into zethrene: A hitherto unknown dehydroannulene and a forgotten aromatic hydrocarbon

Oxidative Cyclodimerization After Tandem Cyclization of Dehydrobenzo[14]annulenes Induced by Alkyllithium

A Direct One‐Pot Synthesis of Asymmetric Dehydrobenzopyrido[12]annulenes and Their Physicochemical Properties

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