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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Chiral organocatalysts based on lipopeptide micelles for aldol reactions in water

Full text
Author(s):
Soares, B. M. ; Aguilar, A. M. ; Silva, E. R. ; Coutinho-Neto, M. D. ; Hamley, I. W. ; Reza, M. ; Ruokolainen, J. ; Alves, W. A.
Total Authors: 8
Document type: Journal article
Source: Physical Chemistry Chemical Physics; v. 19, n. 2, p. 1181-1189, 2017.
Web of Science Citations: 7
Abstract

A comprehensive study of the self-assembly in water of a lipopeptide consisting of a sequence of L-proline, L-arginine and L-tryptophan with a hydrocarbon chain has been performed. Fluorescence assays were used to determine the critical aggregation concentration. In situ small-angle X-ray scattering (SAXS) and molecular dynamics simulations showed the presence of spherical micelles with diameters around 6 nm. In agreement with these results, cryo-TEM images showed globular aggregates with diameters ranging from approximate to 4 nm up to approximate to 9 nm. Furthermore, the lipopeptide catalytic activity has been tested for the direct aldol reaction between cyclohexanone and p-nitrobenzaldehyde, and we have observed that the self-association of the organocatalyst played a critical role in the enhanced activity. Water affects the selectivity, and poor results are obtained under neat reaction conditions. The location of the catalytic groups at the lipopetide/ water solvent interface also endowed unusual selectivity in the catalyzed aldol reactions. Under optimized reaction conditions, high yields (up to >99%), good enantioselectivity (ee up to 85%) and high diastereoselectivity (ds up to 92 : 8) were obtained. (AU)

FAPESP's process: 15/24018-1 - Polymer-Peptide Conjugates for hydrogel formulation and its usage in detection
Grantee:Wendel Andrade Alves
Support Opportunities: Regular Research Grants
FAPESP's process: 08/57805-2 - Institute of Bioanalytics
Grantee:Lauro Tatsuo Kubota
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 13/12674-6 - Structural investigations on model systems based on amphiphilic peptides
Grantee:Emerson Rodrigo da Silva
Support Opportunities: Scholarships in Brazil - Post-Doctoral