From Macrocyclic Oligo-acetylenes to Aromatic Ring <i>Carbo</i>-mers

Maraval, Valérie; Chauvin, Rémi

doi:10.1021/cr050964e

Cited by 102 publications

(64 citation statements)

References 188 publications

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“…In the case of cycloheptatriene (2; Figure 1) and several model tris-homoaromatics such as "in plane" trishomobenzene (3; Figure 1), weak stabilization by through-space homoconjugative interactions has been described. [9] This situation differs from that found in macrocyclic oligoacetylenes and oligodiacetylenes (e.g., pericyclene 4 and 5; Figure 1), [10] compounds which are not homoaromatic and no electron delocalization by homoconjugative interactions between the triple bonds is detected. Only in highly strained cyclic alkynes homoconjugative interactions seem to be appreciable.…”

Section: Introductionmentioning

confidence: 60%

Electron Delocalization in Homoconjugated 7,7‐Diarylnorbornane Systems: A Computational and Experimental Study

Herrero-García

Fernández

Barcina

2011

Chemistry A European J

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A joint computational-experimental study has been carried out to analyze the homoconjugative interactions in 7,7-diarylnorbornane (DPN) derivatives. The experimentally observed new bands in their UV/Vis have been accurately assigned by means of TD-DFT calculations. Both experimental data and computations show that aromatic homoconjugation in acyclic systems is an effective mechanism for electron delocalization that resembles the situation described for polyphenylenes and polyenes. The effective homoconjugation length in homoconjugated oligomers is in the range of 6-7 aryl rings. The effect of substituents directly attached to the para carbon atom of the DPN moiety have been also studied. We found that the HOMO→LUMO vertical transitions can indeed be modified by the nature of the aromatic substituents in order to provoke dramatic changes in the electronic properties (i.e., in the absorption spectra) of the studied species.

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Section: Introductionmentioning

confidence: 60%

Electron Delocalization in Homoconjugated 7,7‐Diarylnorbornane Systems: A Computational and Experimental Study

Herrero-García

Fernández

Barcina

2011

Chemistry A European J

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“…133 For example, spontaneous trimerization of a chiral binaphthalenediyne under the Hay reaction conditions generated receptors for pyranoside binding (Scheme 62). 134 Some tetramer was also observed in this process.…”

Section: Reactions Of Hydrocarbonsmentioning

confidence: 99%

Aerobic Copper-Catalyzed Organic Reactions

et al. 2013

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24 peroxide [Cu I (pyr)(tpb)] 10 mol % TBHP, 1 atm O 2 , 1:2 AcOH/pyr, rt, 24 h ∼2.5 26 74 g 35 25 n-hexane aldehyde CuCl 2 , 18-crown-6 1 atm O 2 , MeCHO, CH 2 Cl 2 , 70 °C, 24 h 2.4 91 h 9 34a 26 n-decane aldehyde Cu II Cl 16 Pc-AM(PS) 3 equiv of PhCHO, MeCN, 1 atm O 2 , 50 °C 15.4 100 i 61 a See Chart 2 for ligand structures. b Also 28% cyclohexene. c Also 26% cyclohexene. d Mixture of alcohol and hydroperoxide. e Remainder of product is cyclohexene. f Approximately 93:7 of 1-adamantol/2-adamantol. g Approximately 98:2 of 1-adamantol/2-adamantol. h Afforded oxidation products in an approximately 1:1 ratio at the 2-and 3-positions. i Mixture of decanones.

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“…Melting points are uncorrected. 1 H and 13 C NMR spectra are collected at 27°C in CDCl 3 , CD 2 Cl 2 , THF-d 8 , and (CD 3 ) 2 CO; solvent peaks as reference. Coupling constants are reported as observed (±0.5 Hz).…”

Section: ■ Conclusionmentioning

confidence: 99%

Donor- and/or Acceptor-Substituted Expanded Radialenes: Theory, Synthesis, and Properties

et al. 2014

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ABSTRACT:The synthesis of donor-(D) and/or acceptor (A)-expanded [4]radialenes has been developed on the basis of readily available dibromoolefin (7), tetraethynylethene (10 and 20), and vinyl triflate (12) building blocks. The successful formation of D/A radialenes relies especially on (1) effective use of a series alkynyl protecting groups, (2) Sonogashira crosscoupling reactions, and (3) the development of ring closing reactions to form the desired macrocyclic products. The expanded [4]radialene products have been investigated by spectroscopic (UV−vis absorption and emission) and quantum chemical computational methods (density functional theory and time dependent DFT). The combined use of theory and experiment provides a basis to evaluate the extent of D/A interactions via the cross-conjugated radialene framework as well as an interpretation of the origin of D/A interactions at an orbital level. ■ INTRODUCTIONConjugated carbon-rich macrocycles are intriguing targets of study for both theoretical and experimental chemists because of their often symmetrical shape and aesthetically appealing structures. They are, however, useful molecules as well, with potential as the organic component for electronic, optical, and nonlinear optical applications.1−8 A specific subcategory of conjugated macrocycles are the [n]radialenes, which are cyclic, carbon-rich molecules with a general formula C 2n H 2n that contain n ring atoms and n exocyclic double bonds (1, Figure 1). "Expanded radialenes" are derivatives of radialenes that originate by formal insertion of an unsaturated spacer between each pair of exomethylene fragments of a radialene, giving rise to macrocycles such as 2 and 3 (Figure 1). 8−12 Work with expanded radialenes was pioneered by Diederich and co-workers 13−16 via the introduction of diacetylene moieties into the radialene framework to give derivatives with the general structure 3 17,18 as well as structurally related radiannulenes.19−27 More recently, expanded radialenes 2 composed of repeating enyne units have been realized and studied. 28−30The two-dimensionally (2D) conjugated structure of expanded [n]radialenes is rather special because it combines a number of linearly and cross-conjugated pathways placed on a nonbenzoid carbon framework.31−39 One key question concerning the properties of expanded [n]radialenes has been the role played by cross-conjugation 9,40,41 to the overall electronic makeup of these unique molecules. The influence of D−A or D/A interactions 42 via cross conjugation in acyclic systems has been explored by a number of groups. 9,10,43−46 To date, however, only a few examples of donor-or acceptor-expanded radialenes have been reported. 18,28 Finally, donor−acceptor-expanded radialenes remain unknown, and there have been no attempts to document cross-conjugated interactions in these derivatives using theory.Our group has recently reported a modular approach for the synthesis of perphenylated expanded [n]radialenes 29 and radiaannulenes. 22,29 This approach has been especially useful ...

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From Macrocyclic Oligo-acetylenes to Aromatic Ring Carbo-mers

Cited by 102 publications

References 188 publications

Electron Delocalization in Homoconjugated 7,7‐Diarylnorbornane Systems: A Computational and Experimental Study

Electron Delocalization in Homoconjugated 7,7‐Diarylnorbornane Systems: A Computational and Experimental Study

Aerobic Copper-Catalyzed Organic Reactions

Donor- and/or Acceptor-Substituted Expanded Radialenes: Theory, Synthesis, and Properties

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