Preparation of enantiomerically pure p-substituted phenylethyl hydroperoxides by kinetic resolution and their use as enantioselective oxidants in the asymmetric Weitz-Scheffer epoxidation of E-chalcone

Zilbeyaz K., KILIÇ H., ŞİŞECİOĞLU M., ÖZDEMİR H., Güngör A. A.

TETRAHEDRON-ASYMMETRY, cilt.23, sa.8, ss.594-601, 2012 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 23 Sayı: 8
  • Basım Tarihi: 2012
  • Doi Numarası: 10.1016/j.tetasy.2012.04.005
  • Dergi Adı: TETRAHEDRON-ASYMMETRY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.594-601
  • Atatürk Üniversitesi Adresli: Evet

Özet

The kinetic resolution of a variety of secondary para-substituted phenylethyl hydroperoxides by Raphanus sativus L (black radish peroxidase) in the presence of guaiacol is reported. The peroxidase enzyme recognized (R)-configured alkyl aryl hydroperoxides, which furnished optically active (S)-hydroperoxides and (R)-alcohols. Kinetic resolution of tertiary hydroperoxides by the enzyme was unsuccessful. This study also shows how the optically active p-substituted (S)-hydroperoxides obtained can be employed as enantioselective oxidants in the asymmetric Weitz-Scheffer epoxidation of E-chalcone in the presence of KF-Al2O3 as a base. In all cases, a chalcone epoxide with the (alpha S,beta R)-configuration was obtained as the major isomer. Under the optimized reaction conditions, the enantiomeric excess of the chalcone epoxide was obtained in up to 49% in CH3CH at -40 degrees C. (C) 2012 Elsevier Ltd. All rights reserved.