Synthesis of an Aza Chiral Crown Ether Grafted to Nanofibrous Silica Support and Application in Asymmetric Michael Addition

Péter L. Sóti, Lorinc Telkes, Zsolt Rapi, András Tóth, Tamás Vigh, Zsombor K. Nagy, Péter Bakó, György Marosi

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

We report on the synthesis of a new, supported phase transfer catalyst and its asymmetric induction. An inorganic-polymer-supported chiral crown ether was prepared by the reaction between an optically active macrocycle deriving from methyl-α-d-glucopyranoside and silica nanofibres. The inorganic carrier of the catalyst has high specific surface area due to its nanofibrous structure, which is favourable for heterogeneous catalytic reactions. SiO2 fibres were electrospun from silica sol which was prepared via sol-gel reactions from tetraethylorthosilicate. The asymmetric Michael reaction of diethyl acetamidomalonate and β-nitrostyrene was selected for the comparison of the performance of various glucopyranoside-based macrocycles. The asymmetric inductions of macrocycles provided 20-99 % enantiomeric excess. A triethoxysilyl derivative was prepared from the highly enantioselective macrocycle in order to immobilize it on the surface of the silica nanofibres. The supported glucose based monoaza-15-crown-5 type macrocycle was characterized by X-ray photoelectron spectroscopy and compared with non-supported native crown ethers in the asymmetric Michael addition. The immobilized phase-transfer catalyst generated high enantiomeric excess (82 %) in spite of the fact that it was used in a three-phase reaction.

Original languageEnglish
Pages (from-to)713-721
Number of pages9
JournalJournal of Inorganic and Organometallic Polymers and Materials
Volume24
Issue number4
DOIs
Publication statusPublished - Jul 2014

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Keywords

  • Asymmetric induction
  • Inorganic polymer nanofibres
  • Phase transfer catalysis
  • Supported chiral crown ether

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry

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