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Chiral organocatalysts based on lipopeptide micelles for aldol reactions in water.
Soares, B M; Aguilar, A M; Silva, E R; Coutinho-Neto, M D; Hamley, I W; Reza, M; Ruokolainen, J; Alves, W A.
Afiliación
  • Soares BM; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, Brazil. wendel.alves@ufabc.edu.br.
  • Aguilar AM; Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema 09972270, Brazil.
  • Silva ER; Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil.
  • Coutinho-Neto MD; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, Brazil. wendel.alves@ufabc.edu.br.
  • Hamley IW; Department of Chemistry, University of Reading, Whiteknights, Reading RG6 6AD, UK.
  • Reza M; Department of Applied Physics, Aalto University School of Science, P. O. Box 15100, FI-00076, Finland.
  • Ruokolainen J; Department of Applied Physics, Aalto University School of Science, P. O. Box 15100, FI-00076, Finland.
  • Alves WA; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, Brazil. wendel.alves@ufabc.edu.br.
Phys Chem Chem Phys ; 19(2): 1181-1189, 2017 Jan 04.
Article en En | MEDLINE | ID: mdl-27942644
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 ≈4 nm up 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.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Lipopéptidos / Micelas Idioma: En Revista: Phys Chem Chem Phys Asunto de la revista: BIOFISICA / QUIMICA Año: 2017 Tipo del documento: Article País de afiliación: Brasil Pais de publicación: Reino Unido
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Lipopéptidos / Micelas Idioma: En Revista: Phys Chem Chem Phys Asunto de la revista: BIOFISICA / QUIMICA Año: 2017 Tipo del documento: Article País de afiliación: Brasil Pais de publicación: Reino Unido