ChemInform Abstract: FULVENES AND FULVALENES. 40. OXIDATIVE COUPLING OF HUECKEL ANIONS: A SIMPLE APPROACH TO FULVALENES

Rutsch, W.; Escher, A.; Neuenschwander, Markus

doi:10.1002/chin.198339176

Cited by 7 publications

(9 citation statements)

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“…Our suggestion comes from the fact that the anion of 1,3-cyclopentadiene upon oxidation gives the corresponding dimer, which can be in turn oxidized to give an analogous compound. [20] The highly conjugated structure of 4a is in agreement with its very intense and bathochromically shifted UV-vis band. In any case we do not exclude that also 4a is a mixture of different compounds.…”

Section: Electrochemical Analysis Of Methyl A-capped Dithienylcyclopesupporting

confidence: 56%

Thiophene/cyclopentadiene regular copolymers from electrochemical oxidation of dithienylcyclopentadienes

Berlin

Zotti

Zecchin

et al. 2002

Macromol. Chem. Phys.

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Section: Electrochemical Analysis Of Methyl A-capped Dithienylcyclopesupporting

confidence: 56%

Thiophene/cyclopentadiene regular copolymers from electrochemical oxidation of dithienylcyclopentadienes

Berlin

Zotti

Zecchin

et al. 2002

Macromol. Chem. Phys.

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“…Schema Dieser Plan wurde am Beispiel des bekannten [l I] Dibenzopentafulvalens 9b optimiert (Ausbeute uber alle Stufen ca. 60%) [lo] [12] [13], sodann auf das seit langem nachgewiesene 191, jedoch spektroskopisch weitgehend unbekannte Pentafulvalen (9a) angewandt (Ausbeute uber alle Stufen ca. 65 % [ 131) und kurzlich zur Synthese des bisher unbekannten extrem reaktiven Nonapentafulvalens (10) herangezogen (Ausbeute uber alle Stufen bzgl.…”

Section: Schema 1 Resultate Uonunclassified

Nonafulvalen: Synthese durch oxidative Kupplung von Cyclononatetraenid und Valenzisomerisierung

Escher

Neuenschwander

Engel

1987

Helvetica Chimica Acta

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Following a general strategy (Scheme 2) for the synthesis of fulvalenes by oxidative coupling of ffiickel anions, the synthesis of nonafulvalene (1) has been realised (Scheme 3 ) . The most tricky step is a twofold deprotonation of bi(cyclononatetraeny1) 3 with K(t-BuO) to give 4; it is only possible after equilibration 3~3 a ; otherwise, deprotonation of one cyclononatetraene unit of 3 followed by oxidative coupling with AgBF4 gives quater(cyclononatetraeny1) I2 as an isomeric mixture. The reaction of 3 with K gives potassium ccct-cyclononatetraenide 11 (M = K; Scheme 5 ) and not the dianion 4 as reported in the literature. Nonafulvalene (1) is extremely reactive due to its very easy valence isomerisation to give an isomeric mixture of tetrahydro-dibenzopentafulvalenes 13 (Scheme 4 ) . The structure of crystalline isomer (E-anti)-13 has been proved by X-ray analysis. 1.Einleitung. -Nonafulvalen (1) ist sowohl synthetisch reizvoll wie theoretisch attraktiv, denn spektroskopische Untersuchungen von 1 konnten in Analogie zu den NMR-Ergebnissen von Nonafulvenen [3] wichtige Aufschlusse uber die Geometrie sowie die Bindungslangenalternanz in diesen cyclisch gekreuzt konjugierten 71 -Systemen geben. Bisher sind jedoch nur vereinzelte hochanellierte und arylierte Nonafulvalene bekannt geworden [4], die keine sicheren Aussagen uber die Grundzustandseigenschaften und die Reaktivitat des Grundkorpers 1 zulassen. Die praparativen Erfahrungen mit einfachen Nonafulvenen [5-71 lassen vermuten, dass 1 sowohl schwer zuganglich als auch ausserst reaktiv sei und sich der Isolierung durch rasche (6n +4n + 26)-Valenzisomerisierung der beiden Neunringe entziehen konnte.Hafner et al. beobachteten 1975 [S], dass Lithium-cyclononatetraenid 2 (M = Li) in Gegenwart von I, oder SbCl, n i t rund 30% Ausbeute zu Bi(cyclononatetraeny1) 3

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“…[59] The reaction proves to be quite general and Cu II is often an alternative to Ag I . Thus the pathway of Scheme 1 can be markedly improved by using CuCl 2 in THF at -30°C for the cyclopentadienide coupling (dihydrofulvalene 14 is formed in 84 % yield) [58,71] and, after essentially quantitative deprotonation to 15 (BuLi), a second treatment with CuCl 2 and concentration provides a red solution (ca. 0.3 m) of spectroscopically pure 5.…”

Section: Pentafulvalenes (Fulvalenes)mentioning

confidence: 98%

The Fulvalenes

Halton

2005

Eur J Org Chem

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The fulvalenes are the class of hydrocarbons obtained by formally cross‐conjugating two rings through a common exocyclic double bond. Although the first report of such a compound dates to 1915, study of the series began in earnest only in the 1950s, and even today many of the unsubstituted parent hydrocarbons remain unknown. The following report, the first to specifically address this class of molecules, summarises the information available from research published to the end of 2004 and offers some suggestions for future study. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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ChemInform Abstract: FULVENES AND FULVALENES. 40. OXIDATIVE COUPLING OF HUECKEL ANIONS: A SIMPLE APPROACH TO FULVALENES

Abstract: Durch oxidative Kupplung der Natriumcyclopentadienide (I) mit KupferUH‐chlorid oder Silbertetrafluoroborat, Depmtonierung der gebildeten l,l ′‐Dihydrofulvalene (II) mit Butyllithium und erneute Oxidation der Dilithiumsalze (III) werden die Fulvalene (IV) hergestellt.

Cited by 7 publications

References 0 publications

Thiophene/cyclopentadiene regular copolymers from electrochemical oxidation of dithienylcyclopentadienes

Thiophene/cyclopentadiene regular copolymers from electrochemical oxidation of dithienylcyclopentadienes

Nonafulvalen: Synthese durch oxidative Kupplung von Cyclononatetraenid und Valenzisomerisierung

The Fulvalenes

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