Design of new chiral phase-transfer catalysts with dual functions for highly enantioselective epoxidation of α,β-unsaturated ketones

Takashi Ooi, Daisuke Ohara, Masazumi Tamura, Keiji Maruoka

Research output: Contribution to journalArticlepeer-review

190 Citations (Scopus)

Abstract

A new chiral ammonium bromide, 1-Br, possessing diarylmethanol functionality as a substrate recognition site has been designed as a promising, dual-functioning catalyst for the highly enantioselective epoxidation of α,β-unsaturated ketones under mild phase-transfer conditions. For instance, vigorous stirring of a mixture of chalcone, 1-Br (3 mol %), and 13% NaOCl in toluene at 0 °C for 24 h gave rise to epoxy chalcone quantitatively with 96% ee. A variety of α,β-unsaturated ketones can also be epoxidized with rigorous stereochemical control, clearly demonstrating the effectiveness and utility of the present system. Further, a successful single-crystal X-ray diffraction analysis of 1-PF6 uncovered its distinctive three-dimensional molecular architecture and provided useful information for postulating the transition state.

Original languageEnglish
Pages (from-to)6844-6845
Number of pages2
JournalJournal of the American Chemical Society
Volume126
Issue number22
DOIs
Publication statusPublished - 2004 Jun 9
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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