Diäthinylcarbene und 2,4-pentadiinylidene

Hauptmann, Hagen

doi:10.1016/0040-4020(76)80085-3

Cited by 60 publications

(40 citation statements)

References 17 publications

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“…Halogen±lithium exchange of 8 with nBuLi at À100 8C followed by treatment with 1,5-bis(trimethylsilyl)penta-1,4-diyn-3-one (10) [18] and then with TMSCl afforded adduct 11 (Scheme 2). [19] Although the spectral data ( 1 H NMR and 13 C NMR) of the product indicated that it was a single isomer, its configuration was not determined.…”

Section: Resultsmentioning

confidence: 99%

“…After the mixture had been stirred for 2 h at À100 8C, a solution of 1,5-bis(trimethylsilyl)penta-1,4-dien-3-one (10) [18] (14.1 g, 62.6 mmol) in THF (50 mL) was added dropwise over 1 h. After being stirred for 2 h, the mixture was slowly warmed to room temperature, then chlorotrimethylsilane (TMSCl; 7.5 g, 69.3 mmol) was added dropwise over 15 min. After being stirred for 1.5 h at room temperature, the mixture was poured into saturated NaHCO 3 solution and extracted with ether.…”

Section: Methodsmentioning

confidence: 99%

“…If this is the case, the formation of C 36 À represents the first example of a cyclo[36]carbon generated from an organic precursor. Although the intensities of the parent peak relative to those of the fragments depend on the conditions of ionization, relatively strong peaks of C 18 À , C 24 À , and C 30 À were observed. By contrast, C 36 À , which was produced by the loss of six indane fragments from 7 À , was only weakly observed (Figure 5d).…”

mentioning

confidence: 93%

“…Next, it is thought likely that cyclo[n]carbons play a key role during the early stages of fullerene formation. [2] Moreover, it has been proposed that cyclo [12]carbon and cyclo [18]carbon serve as precursors of the hitherto unknown, two-dimensional carbon networks called graphyne and graphdiyne, respectively. [3] Cyclo[n]carbons can be produced by laser vaporization of graphite, but with little selectivity in cluster-size distribution.…”

Section: Introductionmentioning

confidence: 99%

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Expanded Radialenes with Bicyclo[4.3.1]decatriene Units: New Precursors to Cyclo[n]carbons

Tobe

Umeda

Iwasa

et al. 2003

Chemistry A European J

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A new method for the formation of conjugated polyynes has been developed based on both the rearrangement of vinylidenes to alkynes and the [2+1] cheletropic fragmentation of dialkynylmethylenebicyclo[4.3.1]deca-1,3,5-triene derivatives. A model study of the photolysis of simple dialkynylmethylenebicyclo[4.3.1]deca-1,3,5-trienes resulted in cheletropic fragmentation followed by 1,2-migration to give the corresponding linear polyynes, although undesired isomerization to methylenebicyclo[5.3.0]triene derivatives took place concurrently. Expanded [3]-, [4]-, [5]-, and [6]radialene derivatives with exocyclic bicyclo[4.3.1]decatriene units were prepared by oxidative coupling of the monomeric units as precursors to the corresponding cyclo[n]carbons, monocyclic forms of carbon clusters. The spectroscopic properties of the expanded radialenes were investigated in connection with cross conjugation of the core pi system and with its perturbation by the extraannular bicyclic pi system. In negative-mode laser-desorption time-of-flight (LD-TOF) mass spectra, the expanded radialenes exhibited peaks due to the corresponding cyclo[n]carbon anions (n = 18, 24, 30, and 36) formed by the stepwise loss of the aromatic indane fragments.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Expanded Radialenes with Bicyclo[4.3.1]decatriene Units: New Precursors to Cyclo[n]carbons

Tobe

Umeda

Iwasa

et al. 2003

Chemistry A European J

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“…refs. [16,17] ). Although bicyclopropylidene (19) proved to be efficiently cyclopropanated with functionally substituted carbenes, [18] no cycloadduct of 19 was detected in the attempted cyclopropanation under conditions analogous to those reported for the generation of diethynylmethylenes.…”

Section: Resultsmentioning

confidence: 99%

Structural Parameters and Electronic Interactions in Substituted 1,1-Diethynylcyclopropanes − An Experimental Study

Meijere

Kozhushkov

Boese³

et al. 2002

Eur. J. Org. Chem.

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Keywords: Alkynes / Conjugation / Diethynylcyclopropanes / Small ring systems / Structure elucidation 1,1-Bis(trimethylsilylethynyl)cyclopropane (4) and dimethyl 3,3Ј-(1,1-cyclopropanediyl)bis(2-propynoate) (5) have been prepared by silylation of the known 1-(bromoethynyl)-1-(trimethylsilylethynyl)cyclopropane (7) and by double carboxylation of 1,1-diethynylcyclopropane (3) followed by esterification, in 91 and 74% overall yields, respectively. 7,7-Diethynyldispiro[2.0.2.1]heptane (6) has been synthesized from ethyl dispiro[2.0.2.1]heptane-7-carboxylate (9) by a ten-step sequence in 41% overall yield. Upon UV irradiation, the diacetylene 4 underwent ethylene extrusion, and the resulting bis(trimethylsilylethynyl)carbene dimerized with electron reorganization to give 1,4,8-tris(trimethylsilyl)-3-(trimethylsilylethynyl)oct-3-ene-1,5,7-triyne (20) (24% yield). X-ray crystal structure analyses of 4, 5, and 6 revealed strong electronic

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En Route to 7,7,8,8-Tetraethynyl-p-quinodimethane (TEQ)

et al. 2002

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The cross-conjugated 1,1-diethynylethylene derivatives 8b−10b were prepared from the corresponding bromides 16, 19, and 17 by Sonogashira coupling with trimethylsilylethyne and hydrolysis of the TMS-protected intermediates thus formed. Coupling of the tetrabromide 18 with (trimethylsilylethynyl)magnesium bromide in the presence of 1,3-[bis(diphenylphosphanyl)propane]nickel(II) chloride yielded the protected tetraalkyne 32, from which the 7,7,8,8-tetraethynyl-tetrahydro-p-quinodimethane 33 was liberated by fluoride treatment. Although 33 is a highly unstable cross-conjugated hydrocarbon, it could be converted into its tetraphenyl derivative by Sonogashira coupling with phenyl iodide. Both 32 and the corresponding tetraphenyl derivative were oxidized to the 7,7,8,8-tetraethynyl-dihydro-p-quinodimethane derivatives 35 and 36, respectively, on treatment with DDQ in dioxane. Further dehydrogenation of 35 to 34 failed, how-

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Diäthinylcarbene und 2,4-pentadiinylidene

Cited by 60 publications

References 17 publications

Expanded Radialenes with Bicyclo[4.3.1]decatriene Units: New Precursors to Cyclo[n]carbons

Expanded Radialenes with Bicyclo[4.3.1]decatriene Units: New Precursors to Cyclo[n]carbons

Structural Parameters and Electronic Interactions in Substituted 1,1-Diethynylcyclopropanes − An Experimental Study

En Route to 7,7,8,8-Tetraethynyl-p-quinodimethane (TEQ)

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