COMULTICAT · New cooperative multifunctional catalysts derived from Cinchona Alkaloids
6РП — Действия „Мария Кюри“
- Период
- 2006-10-18 → 2008-10-17
- Финансиране от ЕС
- 160 180 €
- Участници
- 1
- Схема
- EIF
Линиите свързват координатора с партньорите.
Накратко на български
Катализаторите от алкалоиди и метали се комбинират, за да създават сложни органични молекули като циклопентените. Този подход позволява по-лесно и прецизно синтезиране на хирални съединения при меки условия.
Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.
Резултати накратко
Final Activity Report Summary - COMULTICAT (New Cooperative Multifunctional Catalysts Derived from Cinchona Alkaloids)
Combinations of organocatalysts and transition metal catalysts can give rise to new reactivities in a wide range of reactions and in certain circumstances maintain the high levels of enantiocontrol. In the first part of the fellowship, a one-pot, multistep reaction cascade to cyclopentenes from alpha, beta-unsaturated ketones and propargylated carbon acids through a combination of organocatalysis and transition metal ion catalysis was developed. Initiated by an amine catalysed Michael addition of propargylated pro-nucleophiles to alpha, beta-unsaturated ketones, the enamine intermediate undergoes an intramolecular attack onto the tethered, copper (I) activated, alkynyl group. Subsequent, protonolysis, hydrolysis and isomerisation steps affords the cyclopentene products in good to excellent yields. The reaction cascade was simple to perform, occurs under mild condions and is broad in scope. In the second part of the fellowship, a mutually compatible and cooperative combination of copper (I) triflate and bifunctional 9-amino (9-deoxy) epicinchona-derived urea compounds for the enantioselective Conia-ene cyclization of alkyne tethered b-ketoester substrates was developed. Demonstrating a powerful concept of combining, in situ, catalytically inactive pre-catalyst ligands with catalytically inactive transition metal ion complexes to reversibly create a catalytically active combination of the two, the reaction was efficient, broad in scope, easy to perform and allows access to chiral cyclopentane products with high enantiocontrol.
Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз
Цел на проекта
Enantiomerically pure substances with the capacity to simultaneously activate two reagents towards one another, offer numerous opportunities for the discovery of powerful, asymmetric bond forming reactions.When a compound possesses a combination of Lewis basic and Lewis acidic sites, has a well-defined chiral pocket constructed around a fairly rigid skeleton and appropriate distances between the two activating groups, the templating of a pro-nucleophile (NuH) and an electrophile via a ternary complex can lead to excellent levels of enantio- and diastereo-control in efficient addition reactions at low catalyst loadings.The synergistic cooperation of multicenters (metal/metal and metal/Lewis base) has been invoked in reactions to reactive imines, aldehydes and electron poor double bonds. However, enantioselective carbon-carbon bond forming addition reactions of NuH to unactivated alkyne and alkene systems have not, despite the synthetic power of creating new carbon-carbon bonds and quaternary stereogenic centres from such unreactive substrates.Here we propose to introduce a number of new families of metal-containing, cooperative multifunctional catalysts derived from the privileged cinchona alkaloid family. Where this idea differs conceptually from other bi functional or multifunctional catalyst systems is that our ligand canopy is intended to bind selectively to soft metal ions via soft ligating groups such as phosphines.The unbound bridgehead nitrogen will retain its basic properties and the combination of strong Lewis base and soft Lewis acid held around the fairly rigid cinchona scaffold should confer new reactivity and stereocontrol over a wide range of reagents and substrattes.Accordingly, we aim to introduce new catalysts, use them to discover new and powerful carbon-carbon and carbon-heteroatom bond forming reactions and ultimately control the arising stereochemistry in these reactions to an impressive degree.
Оригинален текст от CORDIS (на английски).
Участници
- UNIVERSITY OF MANCHESTER · MANCHESTERКоординаторОбединеното кралство
Връзки
Данни: CORDIS, © Европейски съюз