Asymmetric epoxidation of substituted chalcones and chalcone analogues catalyzed by α-d-glucose- and α-d-mannose-based crown ethers

Attila Makó, Zsolt Rapi, György Keglevich, Áron Szöllsy, László Drahos, László Hegeds, Péter Bakó

Research output: Article

37 Citations (Scopus)

Abstract

The chiral monoaza-15-crown-5 lariat ethers annellated to methyl-4,6-O-benzylidene-α-d-glucopyranoside-1 or mannopyranoside 2 have been applied as phase-transfer catalysts in the epoxidation of substituted chalcones and chalcone analogues with tert-butylhydroperoxide resulting in significant asymmetric induction. It was found that the position of the substituents in the aromatic ring of the chalcone had an influence both on the chemical yields and enantiomeric excesses. The lowest enantioselectivities (62-83% ee) were found in the case of ortho-substituted model compounds. The highest ee values (ee of 83-97%) were obtained in the case of para-substituted models. From among the chalcone analogues, the maximum ee (90-92%) was detected for the model compound having α-tert-butyl- and β-aryl groups. Using glucose-based crown ether 1, formation of the (-)-enantiomer was preferred, while applying mannose-based 2 as the catalyst, the (+)-enantiomer was in excess.

Original languageEnglish
Pages (from-to)919-925
Number of pages7
JournalTetrahedron Asymmetry
Volume21
Issue number8
DOIs
Publication statusPublished - jún. 11 2010

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ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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