Discovery and Application of Doubly Quaternized Cinchona-Alkaloid-Based Phase-Transfer Catalysts

We report the discovery of novel N,N′‐disubstituted cinchona alkaloids as efficient phase‐transfer catalysts for the assembly of stereogenic quaternary centers. In comparison to traditional cinchona‐alkaloid‐based phase‐transfer catalysts, these new catalysts afford substantial improvements in enant...

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Published inAngewandte Chemie Vol. 126; no. 32; pp. 8515 - 8518
Main Authors Xiang, Bangping, Belyk, Kevin M., Reamer, Robert A., Yasuda, Nobuyoshi
Format Journal Article
LanguageEnglish
German
Published Weinheim WILEY-VCH Verlag 04.08.2014
WILEY‐VCH Verlag
Wiley Subscription Services, Inc
Subjects
Alkaloids
Assembly
Asymmetrische Synthese
Catalysis
Catalysts
Chemistry
Enantioselektivität
Organokatalyse
Phasentransferkatalyse
Spiroverbindungen
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Summary:We report the discovery of novel N,N′‐disubstituted cinchona alkaloids as efficient phase‐transfer catalysts for the assembly of stereogenic quaternary centers. In comparison to traditional cinchona‐alkaloid‐based phase‐transfer catalysts, these new catalysts afford substantial improvements in enantioselectivity and reaction rate for intramolecular spirocyclization reactions with catalyst loadings as low as 0.3 mol % under mild conditions. Eine doppelt positive Entwicklung: N,N′‐disubstituierte Cinchona‐Alkaloide erwiesen sich als hoch effiziente Phasentransferkatalysatoren für den Aufbau quartärer Stereozentren. Gegenüber klassischen Cinchona‐Phasentransferkatalysatoren bieten sie eine deutliche Verbesserung der Enantioselektivität und Reaktivität in intramolekularen Spirocyclisierungen bei Katalysatormengen von nur 0.3 Mol‐% unter milden Reaktionsbedingungen (siehe Beispiel).
Bibliography:istex:6FC4C5B3E5754E1A7F06F0F48F59B620BE1AB306
ArticleID:ANGE201404084
We acknowledge Zhijian Liu, Brian T. Kim, and Szilvia Kiss for the preparation of substrates and useful discussions. We also acknowledge Joe Armstrong, Kevin R. Campos, John Y. L. Chung, Cameron Cowden, Stephen M. Dalby, Ian Davies, David L. Hughes, Shen-chun Kuo, Jinchu Liu, Michael R. Luzung, Carmela Molinaro, Benjamin D. Sherry, David Thaisrivongs, and Jianguo Yin for critical discussions.
ark:/67375/WNG-5311RB03-1
We acknowledge Zhijian Liu, Brian T. Kim, and Szilvia Kiss for the preparation of substrates and useful discussions. We also acknowledge Joe Armstrong, Kevin R. Campos, John Y. L. Chung, Cameron Cowden, Stephen M. Dalby, Ian Davies, David L. Hughes, Shen‐chun Kuo, Jinchu Liu, Michael R. Luzung, Carmela Molinaro, Benjamin D. Sherry, David Thaisrivongs, and Jianguo Yin for critical discussions.
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
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ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201404084