Enantioselective cyclopropanation of conjugated cyanosulfones using carbohydrate-based crown ether catalysts

Tamás Nemcsok, Zsolt Rapi, Péter Bagi, Ying Hou Guan, István Orbán, György Keglevich, Péter Bakó

Research output: Contribution to journalArticle

Abstract

A few new D-galactose- and D-glucose-based monoaza-15-crown-5 type lariat ethers have been synthesized. These macrocycles and their derivatives proved to be efficient catalysts in the cyclopropanation of (E)-3-phenyl-2-(phenylsulfonyl)acrylonitrile performed with diethyl bromomalonate under mild phase transfer conditions. Among the catalysts tested, the macrocycle having methyl α-D-galactopyranoside unit generated the highest asymmetric induction (80% ee). In the reactions of the aryl-substituted phenylsulfonyl-acrylonitrile derivatives, the cyclopropanation of the meta- and para-substituted starting materials took place with high ee values (75–84% ee). The cyclopropane derivatives synthesized from analogous α,β-unsaturated cyanosulfones containing naphthyl, pyridyl, furyl and thienyl groups were obtained with enantioselectivities up to 85%, and in excellent yields.

Original languageEnglish
Article number130965
JournalTetrahedron
Volume76
Issue number9
DOIs
Publication statusPublished - Feb 28 2020

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Keywords

  • Chiral crown ethers
  • Enantioselective cyclopropanation
  • Phase transfer catalysis

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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