Organocatalytic Asymmetric Michael Addition of 4-Hydroxycoumarin to β,γ-Unsaturated α-Keto Esters
نویسندگان
چکیده
منابع مشابه
Organocatalytic asymmetric Michael-type reaction between β,γ-unsaturated α-keto ester and α-nitro ketone.
A Michael-type reaction of β,γ-unsaturated α-keto ester and α-nitro ketone was established. With a thiourea catalyst derived from cinchona alkaloid, the reactions afford products in 47-94% yields with 68-96% ee.
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The first organocatalytic enantioselective direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam to nitroolefins is developed using cinchona alkaloids as the catalysts. Both product enantiomers are accessible with moderate to good enantioselectivity.
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We report an asymmetric oxy-Michael addition to a γ-hydroxy-α,β-unsaturated thioester via hemiacetal intermediates in the presence of Cinchona-alkaloid-thiourea-based bifunctional organocatalysts. This method provides a novel enantioselective route to β-hydroxy carboxyl compounds, which in turn can be used to synthesize valuable chiral building blocks.
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Highly enantioselective organocatalytic Michael addition of ketones to vinyl sulfone catalyzed by a cinchona alkaloid-derived primary amine is reported for the first time; the described synthetic methodology was applied to the synthesis of sodium cyclamate.
متن کاملOrganocatalytic asymmetric addition of malonates to unsaturated 1,4-diketones
The organocatalytic Michael addition of malonates to symmetric unsaturated 1,4-diketones catalyzed by thiourea and squaramide derivatives with Cinchona alkaloids afforded the formation of a new C-C bond in high yields (up to 98%) and enantiomeric purities (up to 93%). The absolute configuration of the product was suggested from comparison of the experimental and calculated VCD spectra of the re...
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ژورنال
عنوان ژورنال: Bulletin of the Korean Chemical Society
سال: 2013
ISSN: 0253-2964
DOI: 10.5012/bkcs.2013.34.6.1623