High enantioselective Michael addition of malonates to β,γ-unsaturated α-ketoesters catalyzed by bifunctional thioureas |
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Authors: | Swapna Konda John C-G Zhao |
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Institution: | Department of Chemistry, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249-0968, USA |
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Abstract: | A highly enantioselective Michael addition of malonates to β,γ-unsaturated α-ketoesters was achieved using cinchona alkaloid-derived thioureas as the bifunctional catalyst. The corresponding Michael addition products were obtained in excellent yields (90–99%) and ee values (up to >99% ee) using a quinidine-derived thiourea as the catalyst under neat conditions. The opposite enantiomer may be obtained using a quinine- or cinchonidine-derived thiourea as the catalyst. |
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Keywords: | Organocatalysis Michael addition Cinchona alkaloid thiourea Malonate Ketoester |
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