Formation of [5.5]cyclopentadienidophanes by macrocyclization of [3-(methylammonio)propyl]cyclopentadienides under Mannich conditions

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Details zur Publikation

Autor(en): Schatz J
Zeitschrift: Tetrahedron
Verlag: Elsevier
Jahr der Veröffentlichung: 2009
Band: 65
Seitenbereich: 5733-5738
ISSN: 0040-4020


2-Acyl-1,4-bis(methoxycarbonyl)-3-[3-(methylammonio)propyl]cyclopentadienides 1 and aqueous formaldehyde can undergo a double Mannich reaction leading to the bisbetainic 2,12-diazonia-[5,5](1,3)cyclopentadienidophanes 2. The success of this macrocyclization reaction seems to depend on the length of the ω-ammonioalkyl chain and the individual acyl substituent. In the cases of ω-(methylammonio)butyl and ω-(methylammonio)pentyl chains, as well as with ω-ammoniopropyl derivatives bearing particularly electron-rich 4-methoxybenzoyl or 2-furoyl substituents, a mixture of oligomers is formed. On the other hand, DCC-assisted cyclocondensation of 1b,d (acyl=4-methoxybenzoyl and thiophene-2-carbonyl, respectively) occurs only intramolecularly, leading to the bicyclic 6-aminopentafulvenes 4b,d in good yields. © 2009 Elsevier Ltd. All rights reserved.

FAU-Autoren / FAU-Herausgeber

Schatz, Jürgen Prof. Dr.
Professur für Organische Chemie

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