2003 Oxirane derivatives

Oxirane derivativesR 0030 Enantioselective Epoxidation of α,β-Unsaturated Ketones by Phase-Transfer Ca-

talysis Using Chiral Quaternary Ammonium Salts. — Asymmetric epoxidation of the chalcone derivatives (II) with sodium hypochlorite under phase-transfer-catalyzed conditions affords the corresponding epoxy ketones (III) in good yields with moderate to good enantiomeric excess. Preparation and optimization of the new phase-transfer catalyst (I) obtained in a two-step procedure from cinchona alkaloids are described. — (KIM*, D. Y.; CHOI, Y. J.; PARK, H. Y.; JOUNG, C. U.; KOH, K. O.; MANG, J. Y.; JUNG, K.-Y.; Synth. Commun. 33 (2003) 3, 435-443; Dep. Chem., Soonchun-hyang Univ., Chungnam 336-600, S. Korea; Eng.) — H. Haber

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