1065010-97-0Relevant academic research and scientific papers
Improving the Catalytic Performance of (S)-Proline as Organocatalyst in Asymmetric Aldol Reactions in the Presence of Solvate Ionic Liquids: Involvement of a Supramolecular Aggregate
Obregón-Zú?iga, Arturo,Milán, Mario,Juaristi, Eusebio
, p. 1108 - 1111 (2017)
For the first time, a highly efficient and stereoselective asymmetric aldol reaction employing (S)-proline in the presence of solvate ionic liquids is reported. The reaction seems to proceed via a supramolecular aggregate of (S)-proline, the solvate ionic
Proline-Glycine Dipeptidic Derivatives of Chiral Phosphoramides as Organocatalysts for the Enantiodivergent Aldol Reaction of Aryl Aldehydes and Isatins with Cyclohexanone in the Presence of Water
Cruz-Hernández, Carlos,Hernández-González, Perla E.,Juaristi, Eusebio
, p. 3445 - 3459 (2018)
The synthesis of several novel organocatalysts derived from (R)- and (S)-proline-glycine dipeptides and incorporating a chiral phosphoramide fragment was accomplished. These chiral compounds catalyze the enantioselective aldol addition reaction of cyclohe
Multifunctional phosphoramide-(S)-prolinamide derivatives as efficient organocatalysts in asymmetric aldol and Michael reactions
Cruz-Hernández, Carlos,Landeros, José M.,Juaristi, Eusebio
supporting information, p. 5455 - 5465 (2019/04/05)
The synthesis and evaluation of three novel chiral organocatalysts derived from (S)-proline and containing a bis-amidophosphoryl amine fragment are reported. The structure and conformation of the new compounds were determined by NMR spectroscopy and X-ray crystallographic analysis. The present study represents an effort directed to enhance the performance of (S)-proline-derived organocatalysts in asymmetric aldol and Michael reactions by means of increased steric interactions arising from the incorporation of naphthyl moieties in the catalysts. In the event, the stereoselectivity achieved with naphthyl substituents turned out to be rather similar to that obtained with phenyl analogs. Nevertheless, the new organocatalysts exhibited rather good enantio- and diastereoselectivities in aldol reactions with various isatins and aryl carbaldehydes, affording products with up to 94?:?6 diastereomeric ratios and enantiomeric ratios as high as 95?:?5. Furthermore, products obtained from Michael addition reactions exhibited up to 96?:?4 diastereomeric ratios and enantiomeric ratios as high as 98?:?2.
(2S,4R)-Hyp-(S)-Phe-OMe dipeptide supported on imidazolium tagged molecules as recoverable organocatalysts for asymmetric aldol reactions using water as reaction medium
Obregón-Zú?iga, Arturo,Juaristi, Eusebio
, p. 5373 - 5380 (2017/08/11)
Four novel chiral imidazolium tagged molecules derived from dipeptide (2S,4R)-Hyp-(S)-Phe-OMe were prepared and evaluated as organocatalysts in the asymmetric aldol reaction using water as solvent. It was found that catalysts incorporating the hexanoyl linker are active down to 5 mol% and afford aldol products with up to 94% yield, up to 98:2 dr and up to 97:3 er. This chiral imidazolium catalyst was reused up to 6 times without any loss in the stereoselectivity of asymmetric aldol reactions. By contrast, organocatalysts containing an acetyl linker proved to be highly unstable in protic solvents, and for that reason they could not be recovered and reused.
Enantioselective aldol reaction of cyclic ketones with aryl aldehydes catalyzed by a cyclohexanediamine derived salt in the presence of water
Lin, Jin-Hong,Zhang, Cheng-Pan,Xiao, Ji-Chang
supporting information; experimental part, p. 1750 - 1753 (2011/03/20)
Water was found to be a suitable reaction medium for the direct asymmetric aldol reaction of various cyclic ketones with aryl aldehydes catalyzed by a primary-tertiary diamine-Bronsted acid. The Royal Society of Chemistry 2009.
