Asymmetric Michael Addition of α-Hydroxyketones to Nitroolefins Catalyzed by Chiral Diamine.
نویسندگان
چکیده
منابع مشابه
Chiral phosphoproline-catalyzed asymmetric Michael addition of ketones to nitroolefins: an experimental and theoretical study.
A novel pyrrolidine-based chiral phosphoproline is an effective bifunctional organocatalyst for the asymmetric Michael addition of ketones to nitroolefins giving high levels of diastereo- and enantio-selectivities (up to > 99 : 1 dr and 96% ee). anti-SR Transition state has the lowest barrier which controls the stereoselectivity, in agreement with experimental results.
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α-Fluoro-α-nitro esters were used as reaction partners in Michael addition to nitroalkenes, and the products were obtained in excellent chemical yields and with high enantioselectivities. Moreover, α-fluoro-α-amino ester with a quaternary α-carbon was prepared for the first time.
متن کاملOrganocatalytic asymmetric direct vinylogous Michael addition of α,β-unsaturated γ-butyrolactam to nitroolefins.
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.
متن کاملCamphor-derived C1-symmetric chiral diamine organocatalysts for asymmetric Michael addition of nitroalkanes to enones.
A series of stable C(1)-symmetric chiral diamines (2a–2l) were conveniently synthesized by condensing exo-(-)-bornylamine or (+)-(1S,2S,5R)-menthylamine with various commercially available Cbz-protected amino acids. Among them, 2a can efficiently promote the Michael addition of nitroalkanes to a broad scope of enones with high yields (up to 96%) and excellent enantioselectivities (up to 98%) un...
متن کاملAsymmetric Michael addition of α-fluoro-α-nitroalkanes to nitroolefins: facile preparation of fluorinated amines and tetrahydropyrimidines.
An asymmetric Michael addition of α-fluoro-α-nitroalkanes to nitroolefins was developed, and the products were obtained in good chemical yields and with high stereoselectivities. Highly functionalized adducts provided ready access to fluorinated amines and tetrahydropyrimidines in an optically enriched form.
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ژورنال
عنوان ژورنال: ChemInform
سال: 2003
ISSN: 0931-7597,1522-2667
DOI: 10.1002/chin.200344030