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Base-Catalyzed Pyran Rearrangements of Profisetinidins

  • Daneel Ferreira
  • Jan P. Steynberg
  • Johann F. W. Burger
  • Desmond A. Young

Abstract

Profisetinidins with 2,3-trans-3,4-trans-(-)-fisetinidol units are subject to stereospecific C-ring isomerization under mild basic conditions; whereas, those with 2,3-trans-3,4-cis “upper” units are susceptible to stereoselective pyran rearrangements. In the latter situation, the functionalized tetrahydropyranochromenes are accompanied by analogs in which the resorcinol A- and pyrocatechol B-ring have been interchanged. The formation of these ring interchanged compounds are explicable in terms of a unique 1,3-aryl migration in a quinone-methide intermediate, such a mechanism, however, requiring the inversion of the absolute configuration at the equivalent of 3-C(C) in the biflavanoid precursor. These base-catalyzed pyran rearrangements may have an important bearing on the industrial applications of condensed tannins.

Keywords

Condensed Tannin Absolute Configuration Wood Adhesive Constituent Unit Negative Cotton Effect 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • Daneel Ferreira
    • 1
  • Jan P. Steynberg
    • 1
  • Johann F. W. Burger
    • 1
  • Desmond A. Young
    • 1
  1. 1.Department of ChemistryUniversity of the Orange Free StateBloemfonteinRepublic of South Africa

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