Heptagons in Aromatics: From Monocyclic to Polycyclic

Miao, Qian

doi:10.1002/tcr.201510009

Cited by 25 publications

(8 citation statements)

References 15 publications

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“…6 (R)-8 was also synthesized from (S)-6via a selective mono-debromination by lithiation with n-BuLi and an addition of MeOH/H 2 O to give (R)-7 followed by a Suzuki coupling with 2-(2,7-di-tert-butylpyren-4yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane in 58% yield over two steps. A Scholl-type oxidative cyclodehydrogenation 15 of (R)-8 produced the intriguing (P)-2 embodied with a heptagonal ring 16 in 71% yield, while retaining the original configuration (er 98:02). Influenced by the higher aromaticity of the corresponding ring of pyrene, the unusual ring closure at the 1 position of the pyrene moiety occurred selectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

et al. 2022

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In this manuscript, we portrayed a stereospecific synthesis of C 2 -and C 1 -symmetric pyrene-fused [7]helicene compounds 1 and 2, respectively. Compounds 1 and 2 were synthesized via a one-pot Suzuki coupling−C−H activation and two-step Suzuki coupling−Scholl reaction, respectively, with complete retention of configuration. The synthesized molecules differ in the fusing mode of [7]helicene units with pyrene via sixand seven-membered rings for 1 and 2, respectively. There was a significant difference in the functional properties and enantiomerization barrier of both compounds because of their distinct molecular symmetry as well as fusing mode to pyrene moiety. The heptagon-containing molecule 2 showed remarkable photophysical and chiroptical properties with commendable configurational stability compared to 1 and pristine [7]helicene as well as its [5]helicene congener.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

et al. 2022

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“…Establishing guidelines for the design of nonplanar π-conjugated molecules is crucial for the development of novel functional materials. − Nonplanar π-systems exhibit numerous intriguing properties such as three-dimensional conformations, structural flexibility, high solubility, chirality, and specific intermolecular interactions such as concave–convex interactions. − Manipulating nonplanarity represents a strategy that has offered practical applications including high-performance organic semiconductors, − unique host–guest systems, − and functional supramolecular assemblies. , One representative approach to design nonplanar π-systems is to incorporate seven-membered ring(s) into a fused π-system. Pioneering work in this area dates back to the synthesis of [7]circulene by Yamamoto and co-workers in 1983, , and a variety of curved aromatic hydrocarbons has been reported since. − Among these, the negatively curved nanographene 1 reported by Miao and co-workers is worth noting in light of its molecular design, which is based on inserting a methylene unit into a planar hexa- peri -benzocoronene skeleton (Figure a) .…”

Section: Introductionmentioning

confidence: 99%

Inserting Nitrogen: An Effective Concept To Create Nonplanar and Stimuli-Responsive Perylene Bisimide Analogues

et al. 2019

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Establishing design principles to create nonplanar π-conjugated molecules is crucial for the development of novel functional materials. Herein, we describe the synthesis and properties of dinaphtho[1,8-bc:1′,8′-ef]azepine bisimides (DNABIs). Their molecular design is conceptually based on the insertion of a nitrogen atom into a perylene bisimide core. We have synthesized several DNABI derivatives with a hydrogen atom, a primary alkyl group, or an aryl group on the central nitrogen atom. These DNABIs exhibit nonplanar conformations, flexible structural changes, and ambipolar redox activity. The steric effect around the central nitrogen atom substantially affects the overall structures and results in two different conformations: a nonsymmetric bent conformation and a symmetric twisted conformation, accompanied by a drastic change in electronic properties. Notably, the nonsymmetric DNABI undergoes unique structural changes in response to the application of an external electric field, which is due to molecular motions that are accompanied by an orientational fluctuation of the dipole moment. Furthermore, the addition of a chiral Brønsted base to N-unsubstituted DNABI affords control over the helical chirality via hydrogen-bonding interactions.

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“…The ratios and yield of 1 and 7 were varied depending on the reaction conditions (Table S1). The Scholl-type oxidative cyclodehydrogenation reaction of 7 , to our surprise, selectively yielded compound ( P )- 2 (er 96:04) with a heptagonal ring in 86% yield with the retention of configuration. This is another example of an unexpected Scholl reaction providing an intriguing product.…”

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confidence: 72%

C₂- and C₁-Symmetric Configurationally Stable Pyrene-Fused [5]Helicenes Connected via Hexagonal and Heptagonal Rings

et al. 2021

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In this paper, we describe the stereospecific synthesis and functional properties of C 2- and C 1-symmetric pyrene-fused [5]helicene molecules 1 and 2 connected via hexagonal and heptagonal rings, respectively. Both molecules showed high configurational stability and distinct functional properties, which were attributed to the fusing mode of [5]helicene with the pyrene and molecular symmetry. The estimated Gibbs activation energy for enantiomerization of 2 is one of the highest reported values for any π-conjugated molecules incorporating [5]helicene moiety.

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Heptagons in Aromatics: From Monocyclic to Polycyclic

Cited by 25 publications

References 15 publications

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

Inserting Nitrogen: An Effective Concept To Create Nonplanar and Stimuli-Responsive Perylene Bisimide Analogues

C₂- and C₁-Symmetric Configurationally Stable Pyrene-Fused [5]Helicenes Connected via Hexagonal and Heptagonal Rings

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Heptagons in Aromatics: From Monocyclic to Polycyclic

Cited by 25 publications

References 15 publications

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

Pyrene-Fused [7]Helicenes Connected Via Hexagonal and Heptagonal Rings: Stereospecific Synthesis and Chiroptical Properties

Inserting Nitrogen: An Effective Concept To Create Nonplanar and Stimuli-Responsive Perylene Bisimide Analogues

C2- and C1-Symmetric Configurationally Stable Pyrene-Fused [5]Helicenes Connected via Hexagonal and Heptagonal Rings

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C₂- and C₁-Symmetric Configurationally Stable Pyrene-Fused [5]Helicenes Connected via Hexagonal and Heptagonal Rings