ORGN 144 |
| A variety of asymmetric organocatalytic methods have been described recently, and these studies have established that an array of chiral organic molecules can serve as selective catalysts for a large number of chemical transformations. Chiral organic catalysts that contain both an acidic and a basic/nucleophilic structural unit are of growing importance in the development of asymmetric catalysis. Although, several enantioselective bifunctional organic catalysts have been identified recently, the design and development of new effective and easily accessible bifunctional chiral organic catalysts continues to be a challenging task. Based on our previous results we have designed and synthesized new chiral thiourea-based bifunctional catalysts for asymmetric C-C bond formation reactions. The high potential of these new primary amine derived chiral thioureas for the Michael addition of different ketones to nitroolefins (convenient access to γ-nitroketones which are valuable building blocks in organic synthesis) and Mannich-type reaction of N-protected α-imino ethylglyoxylate with a variety of ketones (general approach to functionalized α-amino acids) is demonstrated for the first time. Excellent enantioselectivities (up to 99% ee) and yields (up to 99%) were observed for both reactions. These research efforts will be discussed in the presentation.
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Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Combinatorial, Parallel, and Solid-Phase Chemistry
8:00 PM-10:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Organic Chemistry |
