Stereoselective ring-opening reactions with AcBr and AcCl. A new method for preparation of some haloconduritols

BARAN A., Kazaz C., Secen H.

TETRAHEDRON, cilt.60, sa.4, ss.861-866, 2004 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 60 Sayı: 4
  • Basım Tarihi: 2004
  • Doi Numarası: 10.1016/j.tet.2003.11.054
  • Dergi Adı: TETRAHEDRON
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.861-866
  • Anahtar Kelimeler: haloconduritol, ring-opening, 7-oxa-bicyclo[2.2.1]hept-5-ene-2,3-diol diacetate, cyclohexa-3,5-diene-cis-1,2-diol, acetyl bromide, acetyl chloride, BROMOCONDURITOL, INHIBITORS
  • Atatürk Üniversitesi Adresli: Evet

Özet

The actions of AcX (X=Br, Cl) on 7-oxa-bicyclo[2.2.1]hept-5-ene-2,3-diol diacetates and a transoid-epoxide prepared from the acetonide of cyclohexa-3,5-diene-cis-1,2-diol were studied. H2SO4-catalyzed cleavage of exo-cis-7-oxa-bicyclo[2.2.1]hept-5-ene-2,3-diol diacetate with AcCl gave (1alpha,2alpha,3alpha,6beta)-6-chloro-4-cyclohexene-1,2,3-triol triacetate, from which the corresponding chloroconduritol was obtained by trans-esterification (MeOH/HCl). A similar reaction of the exo-diacetate with AcBr in the presence of H2SO4 resulted in bromine addition. The formation of bromine from the reaction of AcBr and H2SO4 was observed by independent experiments. H2SO4-catalyzed reaction of etido-cis-7-oxa-bicyclo[2.2.1]hept-5-ene-2,3-diol diacetate with AcX (X=Br, Cl) gave (1alpha,2alpha,3beta,6beta)-6-halo-4-cyclohexene1,2,3-triol triacetates. The reaction of the transoid-epoxide with AcX (X=Br, Cl) with no catalyst gave also (1alpha,2alpha,3beta,6beta)-6-halo-4-cyclohexene-1,2,3-triol triacetates. (C) 2003 Elsevier Ltd. All rights reserved.