New Concepts for Catalysis
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چکیده
Organocatalysis, the catalysis with low-molecular weight catalysts where a metal is not part of the catalytic principle, can be as efficient and selective as metalor biocatalysis. Important discoveries in this area include novel Lewis base-catalyzed enantioselective processes and, more recently, simple Brønsted acid organocatalysts that rival the efficiency of traditional metal-based asymmetric Lewis acid-catalysts. Contributions to organocatalysis from our laboratories include several new and broadly useful concepts such as enamine catalysis and asymmetric counteranion directed catalysis. Our lab has discovered the proline-catalyzed direct asymmetric intermolecular aldol reaction and introduced several other organocatalytic reactions. Introduction: Organocatalysis When chemists make chiral compounds – molecules that behave like object and mirror image, such as amino acids, sugars, drugs, or nucleic acids – they like to use asymmetric catalysis, in which a chiral catalyst selectively accelerates the reaction that leads to one mirror-image isomer, also called enantiomer. For decades, the generally accepted view has been that there are two classes of efficient asymmetric catalysts: enzymes and synthetic metal complexes [1]. However, this view is currently being challenged, with purely organic catalysts emerging as a third class of powerful asymmetric catalysts (Figure 1). 35 http://www.beilstein-institut.de/Bozen2008/Proceedings/List/List.pdf Systems Chemistry, May 26 – 30, 2008, Bozen, Italy
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تاریخ انتشار 2009