Layered Compounds. XXXIV. Molecular and Crystal Structure of a Polycyclic Compound from Novel Cycloaddition Reaction of Triple-layered Anthracenophane

Toyoda, T.; Iwama, A.; Otsubo, Tetsuo; Misumi, Soichi

doi:10.1246/bcsj.49.3300

Cited by 15 publications

(1 citation statement)

References 7 publications

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“…The isomer 5 was obtained in low yield, but in the case of anthracenophane 6(R=CH) an isomeric cage compound 7(R=CH,) was isolated from the reaction mixture in 1.5% yield(7: R=H 8.7% yiel)(ref. 7). The structures of 7 were determined by PMR and X-ray analysis.…”

Section: Thermal Cycloaddition Anthracenophanesmentioning

confidence: 99%

Cycloaddition reactions of cyclophanes

Misumi¹

1987

Pure and Applied Chemistry

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-Unusual thermal and photochemical cycloaddition reactions of the aromatic rings in some cyclophanes are described. For example, the benzene in paracyclo(9,lO)anthracenophane functions as a dienophile in intramolecular DielsAlder reaction and tetracyanoethylene reacts easily with a triple-layered cyclophadiyne even at room temperature to give a 1:1 cycloadduct, suggesting a concerted process of three isolated Tr-systems. The formation of cage compounds by photoinduced cycloaddition and their reverse, thermal ring opening reactions are observed with syn[2.2](1,4)anthracenophane and dihetera quadruple-layered cyclophanes. A quantitative photodimerization of (9,1O)anthracenophadiyne and photoinduced bridge migration of multilayered metaparacyclophanes are discussed.

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Section: Thermal Cycloaddition Anthracenophanesmentioning

confidence: 99%

Cycloaddition reactions of cyclophanes

Misumi¹

1987

Pure and Applied Chemistry

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The IntramolecularDiels–Alder Reaction

Ciganek

1984

Organic Reactions

108

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The Diels–Alder reaction is one of the most useful reactions available to the synthetic organic chemist. It is thus surprising that the intramolecular version, in which both diene and dienophile are part of the same molecule, remained virtually unexplored for many years. Early examples were often the result of unexpected observations, and the many advantages of this reaction were recognized and put to use in the synthesis of complex polycyclic molecules only recently. In the intramolecular Diels–Alder reaction, two rings are formed in one step. In addition to the six‐membered ring formed by the [4 + 2]cycloaddition, the product contains a second ring, the size of which depends on the length of the chain connecting diene and dienophile. Of the two possible regiochemical modes of addition, that leading to the fused product usually predominates to the virtual exclusion of the bridged product. The Diels–Alder reaction proceeds through a highly ordered transition state that is reflected in large negative activation entropies. In the intramolecular version, some of the ordering has been accomplished in advance by making the two reacting functionalities part of the same molecule. This results in less negative activation entropies and increased reaction rates under often surprisingly mild conditions. On the other hand, by using forcing conditions one can sometimes carry out intramolecular Diels–Alder additions that would be doomed to failure in the intermolecular version. Lower reaction temperatures, together with the constraints imposed by the connecting chain, often result in pronounced regio‐ and stereoselectivity. Side reactions such as dimerization or polymerization can be avoided by using high dilution or low pressures in the gas phase. Examples where the bimolecular Diels–Alder reaction interferes with the intramolecular cyclization are rare. All of these features suggest that the intramolecular Diels–Alder reaction should be considered for any synthesis of a molecule containing a six‐membered ring fused to a second ring, especially if that ring is five‐ or six‐membered. Such a synthetic scheme may be made convergent by building up the diene and dienophile portions separately and connecting them just prior to the actual cyclization. Another potential use of the intramolecular Diels–Alder reaction that has not received much attention to date is as a supplement to the intermolecular Diels–Alder reaction in cases where the latter is unsuccessful or gives the wrong regio‐ or stereochemistry. By judicious choice of the connecting chain, the reaction may be made to proceed with the desired selectivity; this is followed by cleavage of the chain and conversion of the two ends to the desired functionalities. Once the feasibility of employing the intramolecular Diels–Alder reaction has been recognized, the main challenge often becomes the preparation of the substrate. A discussion of that aspect is beyond the scope of this chapter; however, by scanning the tables for the particular diene, dienophile, and chain one is interested in, and then referring to the original literature, it will often be possible to obtain some indications on how to proceed. An attempt has been made to cover the literature of the thermal intramolecular Diels–Alder reaction as completely as possible up to and including the year 1981. Many of the papers that appeared in 1982 and some from 1983 have also been included. More recent references are given in an addendum at the end of the tabular survey.

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Koordinationschemische Synthesemethoden zum Aufbau supramolekularer Verbindungen

2001

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Organisch‐präparativ arbeitenden Chemikern steht zur Herstellung von kleinen Molekülen, Nanostrukturen und Polymeren eine breite Palette zuverlässiger Reaktionen zur Verfügung. Koordinationschemiker hingegen sind damit konfrontiert, dass ihnen in der Übergangsmetallchemie im Vergleich zur Chemie des Kohlenstoffs selbst zur Synthese kleiner Molekülstrukturen nur relativ wenige mit hohen Ausbeuten verlaufende Reaktionen offenstehen, wenn man deren Zahl auf die Gesamtzahl der Übergangsmetalle umlegt. Dies liegt hauptsächlich an den im Vergleich zu den starken, kovalenten Bindungen in organischen Molekülen schwachen Metall‐Ligand‐Wechselwirkungen in Koordinationskomplexen. Eine schwache Bindung führt oft zu vielen Reaktionswegen, die sich energetisch nicht wesentlich unterscheiden, und folglich auch zu geringer Selektivität. Als Folge davon kamen viele Koordinationschemiker in den letzten Jahren zu der Erkenntnis, dass es leichter und ergiebiger sein könnte, einfache und zuverlässige Reaktionswege für supramolekulare Strukturen (im Nanomaßstab) so zu entwickeln, dass die wenigen Reaktionen aus der Koordinationschemie eingesetzt werden, die eine hohe Ausbeute liefern. Außerdem soll Kapital geschlagen werden aus den die Reaktionsrichtung dirigierenden Bindungen in den Metallzentren und aus den Strategien, die darauf abzielen, den Vorteil schwacher Metallbindungen in Koordinationskomplexen zu nutzen, um damit solche Architekturen aufzubauen. Die drei sich ergebenden Synthesestrategien, nämlich der „Symmetry‐Interaction“‐Ansatz, der „Directional‐Bonding“‐Ansatz und der „Weak‐Bonding“‐Ansatz nutzen alle Metallzentren als Strukturbausteine, um in gezielter Weise mit molekularen Komponenten supramolekulare Metallocyclophane aufzubauen. Diese drei Konzepte und ihre zugrunde liegenden Prinzipien werden in diesem Aufsatz behandelt, und es werden die sich daraus ergebenden Möglichkeiten verglichen und gegenübergestellt.

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Layered Compounds. XXXIV. Molecular and Crystal Structure of a Polycyclic Compound from Novel Cycloaddition Reaction of Triple-layered Anthracenophane

Cited by 15 publications

References 7 publications

Cycloaddition reactions of cyclophanes

Cycloaddition reactions of cyclophanes

The IntramolecularDiels–Alder Reaction

Koordinationschemische Synthesemethoden zum Aufbau supramolekularer Verbindungen

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