Asymmetric cyclopropanation reactions catalyzed by carbohydrate-based crown ethers

Zsolt Rapi, Tamás Nemcsok, A. Grün, Ádám Pálvölgyi, Gyula Samu, Dóra Hessz, M. Kubinyi, M. Kállay, G. Keglevich, P. Bakó

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8 Citations (Scopus)

Abstract

Optically active cyclopropane derivatives were prepared by a novel, simple and green approach in high enantioselectivities using monosaccharide-based chiral crown ethers as phase transfer catalysts. The crown ethers having D-glucopyranoside, D-mannopyranoside and D-altropyranoside units proved to be efficient catalyst in a few asymmetric phase transfer cyclopropanation reactions. The Michael-initiated ring closure (MIRC) reactions of diethyl bromomalonate with chalcones took place with complete diastereoselectivity and up to 99% ee. Using benzylidenemalononitrile, 2-arylidenemalononitriles, 2-benzylidene-1,3-indandione, substituted 2-benzylidene-1,3-indandiones, 2-arylidene-1,3-indandiones and 2-benzylidene-1,3-diphenyl-1,3-propanediones enantioselectivities up to 92%, 99%, 54% 93%, 89% and 72%, respectively, were achieved, in the presence of chiral lariat ethers derived from different monosaccharides. The absolute configuration of a cyclopropane diester product was determined by a combined CD spectroscopic and theoretical study.

Original languageEnglish
JournalTetrahedron
DOIs
Publication statusAccepted/In press - Jan 1 2018

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Keywords

  • Asymmetric cyclopropanation
  • Chiral crown ethers
  • Enantioselectivity
  • Phase transfer catalysis

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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