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Organocatalytic asymmetric aldol reaction in the presence of water.
Org Biomol Chem. 2007 Jul 07; 5(13):2148-53.OB

Abstract

Water was found to be a suitable solvent for the l-prolinethioamide catalysed aldol reaction of various cyclic ketones with aromatic aldehydes. Treatment of 4-nitrobenzaldehyde with as little as 1.2 equiv. of cyclohexanone in the presence of the protonated catalyst 1-TFA, afforded aldol products in high yields (up to 97%) with high diastereo- and enantioselectivity (up to >5 : 95 dr and 98% ee). The use of a high excess of ketone was avoided by conducting the aldol addition in the presence of water. Furthermore, different 'salting-out' and 'salting-in' salts were investigated and it was proven that the rate of acceleration and the stereochemical outcome of the reaction are affected by hydrophobic aggregation. Scope and limitation studies revealed that electron deficient aldehydes afforded aldol products with high stereoselectivity in the presence of 1-Cl(2)CHCO(2)H. It was shown that various cyclic ketones, under the conditions found, gave aldol products with fair yields, even if they are used in substoichiometric amounts (1.2 to 2.0 equiv.).

Authors+Show Affiliations

Institute of Organic Chemistry of the Polish Academy of Sciences, Kasprzaka 44/52, Warsaw, Poland. dgryko@icho.edu.plNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

17581659

Citation

Gryko, Dorota, and Wojciech J. Saletra. "Organocatalytic Asymmetric Aldol Reaction in the Presence of Water." Organic & Biomolecular Chemistry, vol. 5, no. 13, 2007, pp. 2148-53.
Gryko D, Saletra WJ. Organocatalytic asymmetric aldol reaction in the presence of water. Org Biomol Chem. 2007;5(13):2148-53.
Gryko, D., & Saletra, W. J. (2007). Organocatalytic asymmetric aldol reaction in the presence of water. Organic & Biomolecular Chemistry, 5(13), 2148-53.
Gryko D, Saletra WJ. Organocatalytic Asymmetric Aldol Reaction in the Presence of Water. Org Biomol Chem. 2007 Jul 7;5(13):2148-53. PubMed PMID: 17581659.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Organocatalytic asymmetric aldol reaction in the presence of water. AU - Gryko,Dorota, AU - Saletra,Wojciech J, Y1 - 2007/06/04/ PY - 2007/6/22/pubmed PY - 2007/8/31/medline PY - 2007/6/22/entrez SP - 2148 EP - 53 JF - Organic & biomolecular chemistry JO - Org Biomol Chem VL - 5 IS - 13 N2 - Water was found to be a suitable solvent for the l-prolinethioamide catalysed aldol reaction of various cyclic ketones with aromatic aldehydes. Treatment of 4-nitrobenzaldehyde with as little as 1.2 equiv. of cyclohexanone in the presence of the protonated catalyst 1-TFA, afforded aldol products in high yields (up to 97%) with high diastereo- and enantioselectivity (up to >5 : 95 dr and 98% ee). The use of a high excess of ketone was avoided by conducting the aldol addition in the presence of water. Furthermore, different 'salting-out' and 'salting-in' salts were investigated and it was proven that the rate of acceleration and the stereochemical outcome of the reaction are affected by hydrophobic aggregation. Scope and limitation studies revealed that electron deficient aldehydes afforded aldol products with high stereoselectivity in the presence of 1-Cl(2)CHCO(2)H. It was shown that various cyclic ketones, under the conditions found, gave aldol products with fair yields, even if they are used in substoichiometric amounts (1.2 to 2.0 equiv.). SN - 1477-0520 UR - https://www.unboundmedicine.com/medline/citation/17581659/Organocatalytic_asymmetric_aldol_reaction_in_the_presence_of_water_ L2 - https://doi.org/10.1039/b703254d DB - PRIME DP - Unbound Medicine ER -
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