Synthesis of Fused Oxabicyclic Systems by Metal-Catalyzed Intramolecular Addition of 1,3-Cycloalkyldiones to Alkynes

Gulı́as, Moisés; Rodríguez,; Castedo, Luís; Mascareñas, José L.

doi:10.1021/ol0345632

Cited by 58 publications

(21 citation statements)

References 17 publications

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“…In view of the inherent flexibility of the approach, however, it can be expected that more elaborated and differently functionalized helical compounds are also within reach. [34] Along similar lines, the individual phenyl rings in the starting material can be formally replaced by heteroarene units (entries [12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Although in the case of the N-unprotected pyrrole derivatives 26 a, b one might expect that the nitrogen atom acts as the nucleophile, exclusive carbocyclization with formation of 1H-benzo [g]indoles 27 a, b was observed.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Phenanthrenes and Polycyclic Heteroarenes by Transition‐Metal Catalyzed Cycloisomerization Reactions

Mamane¹,

Hannen²,

Fürstner³

2004

Chemistry A European J

624

254

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Readily available biphenyl derivatives containing an alkyne unit at one of their ortho-positions are converted into substituted phenanthrenes on exposure to catalytic amounts of either PtCl2, AuCl, AuCl3, GaCl3 or InCl3 in toluene. This 6-endo-dig cyclization likely proceeds through initial pi-complexation of the alkyne unit followed by interception of the resulting eta2-metal species by the adjacent arene ring. The reaction is inherently modular, allowing for substantial structural variations and for the incorporation of substituents at any site of the phenanthrene product. Moreover, it is readily extended to the heterocyclic series as exemplified by the preparation of benzoindoles, benzocarbazoles, naphthothiophenes, as well as bridgehead nitrogen heterocycles such as pyrrolo[1,2-a]quinolines. Depending on the chosen catalyst, biaryls bearing halo-alkyne units can either be converted into the corresponding 10-halo-phenanthrenes or into the isomeric 9-halo-phenanthrenes; in the latter case, the concomitant 1,2-halide shift is best explained by assuming a metal vinylidene species as the reactive intermediate. The scope of this novel method for the preparation of polycyclic arenes is illustrated by the total synthesis of a series of polyoxygenated phenanthrenes that are close relatives of the anticancer agent combretastatin A-4, as well as by the total synthesis of the aporphine alkaloid O-methyl-dehydroisopiline and its naturally occurring symmetrical dimer.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Phenanthrenes and Polycyclic Heteroarenes by Transition‐Metal Catalyzed Cycloisomerization Reactions

Mamane¹,

Hannen²,

Fürstner³

2004

Chemistry A European J

624

254

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“…Da das Halogenatom in das Produkt eingebaut wird, sind allerdings stöchiometrische Mengen erforderlich. [191,192] Je nach Reaktionsbedingungen und Substratstruktur können die intermediären Oxonium-Spezies auch auf anderen Wegen weiterreagieren. So liefert Verbindung 147 in Gegenwart katalytischer Mengen an Au III und eines Alkohols das entsprechende 3(2H)-Furanon 148.…”

Section: Angewandte Chemieunclassified

Katalytische carbophile Aktivierung: Platin‐ und Gold‐π‐Säuren als Katalysatoren

2007

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Platin‐ und Goldkatalysatoren gewinnen aufgrund ihrer hohen Effizienz und erstaunlichen Vielfalt für atomökonomische Umsetzungen rasch an Bedeutung. Dabei erlaubt es die Korrelation zwischen ihrem chemischen Verhalten und den vorhandenen Strukturdaten, der bekannten Koordinationschemie und den auf relativistischen Effekten beruhenden Besonderheiten ihrer metallorganischen Derivate, grundlegende Prinzipien der katalytischen carbophilen Aktivierung durch π‐Säuren zu formulieren. Platin‐ und Goldkomplexe sind keinesfalls nur ein umweltfreundlicher Ersatz für stöchiometrische π‐Säuren, sondern sie erweitern das klassische Reaktivitätsspektrum signifikant. Die in der Literatur geläufigen, aber scheinbar widersprüchlichen Erklärungen ihres Verhaltens auf Basis von Metallcarbenen oder metallstabilisierten, “nichtklassischen” Carbokationen als reaktiven Zwischenstufen liefern bei genauer Betrachtung eine vereinheitlichte Grundlage für das Verständnis dieses faszinierenden Gebiets. Hier gilt das Hauptaugenmerk der Verbesserung bekannter sowie der Entwicklung neuer Kupplungs‐, Cycloisomerisierungs‐ und Gerüstumlagerungsreaktionen. Auch der Einsatz Platin‐ und goldkatalysierter Transformationen in Naturstoffsynthesen wird diskutiert.

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“…The known 24 2-siloxy-2cyclohexenone ( 12 ) was converted in two steps to α-silyloxy ketone 13 by Grignard addition followed by base catalyzed silyl migration. 25 The olefin was oxidatively cleaved to the carboxylic acid, which was subsequently converted to diazo ketone 14 under standard conditions. Diazo compound 14 smoothly cyclized to diastereomeric bicycles 15 and 16 in 43 and 45% yield respectively.…”

mentioning

confidence: 99%

A Ring Fragmentation Approach to Medium-Sized Cyclic 2-Alkynones

et al. 2011

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Synthesis of Fused Oxabicyclic Systems by Metal-Catalyzed Intramolecular Addition of 1,3-Cycloalkyldiones to Alkynes

Cited by 58 publications

References 17 publications

Synthesis of Phenanthrenes and Polycyclic Heteroarenes by Transition‐Metal Catalyzed Cycloisomerization Reactions

Synthesis of Phenanthrenes and Polycyclic Heteroarenes by Transition‐Metal Catalyzed Cycloisomerization Reactions

Katalytische carbophile Aktivierung: Platin‐ und Gold‐π‐Säuren als Katalysatoren

A Ring Fragmentation Approach to Medium-Sized Cyclic 2-Alkynones

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