Noncovalent Catalysis for Enantioselective Direct Aldol Reaction of 3‐Acetylcoumarins to Pyrazole‐4,5‐diones
نویسندگان
چکیده
منابع مشابه
The first direct and enantioselective cross-aldol reaction of aldehydes.
The first enantioselective catalytic direct cross-aldol reaction that employs nonequivalent aldehydes has been accomplished using proline as the reaction catalyst. Structural variation in both the aldol donor (R1 = Me, n-Bu, Bn, 91 to >99%) and aldol acceptor (R2 = I-Pr, I-Bu, c-C6H11, Et, Ph, 97-99% ee) are possible while maintaining high reaction efficiency (75-88% yield). Significantly, this...
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A small organic molecule, Pro-NH(2), catalyzing the enantioselective aldol reaction "in water" not merely "in the presence of water" with good enantioselectivity has been discovered for the first time.
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Protonated N'-benzyl-N'-l-prolyl-l-proline hydrazide has been developed as a highly enantioselective catalyst for the asymmetric direct aldol reaction of aromatic aldehydes with ketones.
متن کاملEnantioselective desymmetrization of prochiral cyclohexanone derivatives via the organocatalytic direct Aldol reaction.
Asymmetric desymmetrization of 4-substituted cyclohexanones using proline amide-catalyzed direct aldol reaction afforded beta-hydroxyketones with three stereogenic centers in high enantioselectivities of up to >99% ee.
متن کاملEnantioselective direct aldol reactions catalyzed by L-prolinamide derivatives.
l-Prolinamides 2, prepared from l-proline and simple aliphatic and aromatic amines, have been found to be active catalysts for the direct aldol reaction of 4-nitrobenzaldehyde with neat acetone at room temperature. They give moderate enantioselectivities of up to 46% enantiomeric excess (ee). The enantioselectivity increases as the amide N-H becomes a better hydrogen bond donor. l-Prolinamides ...
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ژورنال
عنوان ژورنال: Asian Journal of Organic Chemistry
سال: 2019
ISSN: 2193-5807,2193-5815
DOI: 10.1002/ajoc.201800732