Macrocyclic cyclophane belts via double Diels-Alder cycloadditions: Macroannulation of bisdienes by bisdienophiles. Synthesis of a key precursor to an [8]cyclacene

Cory, Robert M.; McPhail, Cameron L.; Dikmans, Antonius J.; Vittal, Jagadese J.

doi:10.1016/0040-4039(96)00263-8

Cited by 95 publications

(60 citation statements)

References 7 publications

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“…In this connection, it should be mentioned that cyclic ladder oligomers were also obtained by other research groups, [16][17][18][19][20][21][22] as a consequence of ring-chain equilibria when ladder polymers were prepared by Diels-Alder polyaddition. In contrast to these polyadditions, the cyclic ladder oligomers and polymers of this work are the product of kinetically controlled polycondensations and do not participate in equilibration reactions.…”

Section: Resultsmentioning

confidence: 99%

Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy‐tetramethylspirobisindane with 1,4‐Dicyanotetrafluorobenzene

Kricheldorf

Fritsch

Vakhtangishvili

et al. 2005

Macro Chemistry & Physics

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Summary: 5,5′,6,6′‐Tetra(trimethylsiloxy)‐4,4,4,4′‐tetramethyl‐1,1‐spirobisindane was polycondensed with 1,4‐dicyanotetrafluorobenzene under variation of solvent temperature, time, and feed ratio. Under optimized reaction conditions, all products detectable by MALDI‐TOF mass spectrometry (up to masses around 8 000 Da) proved to be cyclic ladder oligomers and polymers. In N‐methylpyrrolidone and dimethylsulfoxide odd‐numbered cycles were formed in addition to the prevailing even‐numbered ones. However, in sulfolane exclusively even‐numbered cycles were obtained (detectable up to masses around 10 000 Da), together with even‐numbered linear chains. Temperatures above 100 °C enhanced the molecular weights by side reactions. With the less reactive cyano‐2,3,5,6‐tetrafluorobenzene (CTB) again cycles were formed, but their content and the conversions were lower. Polycondensation of CTB up to 160 °C and all polycondensations of cyanopentafluorobenzene gave crosslinked products.Synthesis of cyclic ladder polymers.magnified imageSynthesis of cyclic ladder polymers.

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Section: Resultsmentioning

confidence: 99%

Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy‐tetramethylspirobisindane with 1,4‐Dicyanotetrafluorobenzene

Kricheldorf

Fritsch

Vakhtangishvili

et al. 2005

Macro Chemistry & Physics

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“…In particular, we speculated about the possible cyclotetramerization of the highly reactive 5,6‐didehydroisobenzofuran ( 4 ), which contains both a diene (furan) and a dienophile (aryne) in the same molecule (Scheme a) . In contrast, for the synthesis of rectangularly‐shaped compound, 3 we decided to use two different monomers, a bisdiene and a bisdienophile, similarly to the strategies used by the groups of Stoddart and Cory –. In this case, we envisioned a two‐step synthesis via the double Diels–Alder reaction of bisaryne 5 with benzodifuran equivalent 6 .…”

Section: Figurementioning

confidence: 99%

Exploring a Route to Cyclic Acenes by On‐Surface Synthesis

et al. 2019

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Ar oute to generate cyclacenes by on-surface synthesis is explored. We started by synthesizing two tetraepoxycyclacenes by sequences of Diels-Alder cycloadditions. Subsequently,t hese molecules were deposited onto Cu(111) andscanning-tunneling-microscopy(STM)-based atom manipulation was employed to dissociate the oxygen atoms. Atomic force microscopy(AFM) with CO-functionalized tips enabled the detailed characterization of the reaction products and revealed that, at most, two oxygens per molecule could be removed. Importantly,our experimental results suggest that the generation of cyclacenes by the described route might be possible for larger epoxycyclacenes.

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“…[117] In stark contrast to these advances, the synthesis of the [n]cyclacenes, that is, molecular fragments of zig-zag single-wall CNTs, has not yet been met with similar success. A common problem observed in the different attempted syntheses reported by the research groups of Schlüter, [118] Stoddart, [119,120] and Cory [121,122] is that the final aromatization of promising, partially saturated precursors failed. [112] Theoretical analyses of the [n]cyclacenes indicate that the aromatic stabilization energy may just be insufficient to compensate for the high molecular strain.…”

Section: Synthesis Of Fullerene Fragments Aromatic Belts and "Unusumentioning

confidence: 99%

Nanostructured Carbonaceous Materials from Molecular Precursors

et al. 2010

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Nanostructured carbonaceous materials, that is, carbon materials with a feature size on the nanometer scale and, in some cases, functionalized surfaces, already play an important role in a wide range of emerging fields, such as the search for novel energy sources, efficient energy storage, sustainable chemical technology, as well as organic electronic materials. Furthermore, such materials might offer solutions to the challenges associated with the on-going depletion of nonrenewable energy resources or climate change, and they may promote further breakthroughs in the field of microelectronics. However, novel methods for their preparation will be required that afford functional carbon materials with controlled surface chemistry, mesoscopic morphology, and microstructure. A highly promising approach for the synthesis of such materials is based on the use of well-defined molecular precursors.

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Macrocyclic cyclophane belts via double Diels-Alder cycloadditions: Macroannulation of bisdienes by bisdienophiles. Synthesis of a key precursor to an [8]cyclacene

Cited by 95 publications

References 7 publications

Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy‐tetramethylspirobisindane with 1,4‐Dicyanotetrafluorobenzene

Cyclic Ladder Polymers by Polycondensation of Silylated Tetrahydroxy‐tetramethylspirobisindane with 1,4‐Dicyanotetrafluorobenzene

Exploring a Route to Cyclic Acenes by On‐Surface Synthesis

Nanostructured Carbonaceous Materials from Molecular Precursors

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