Stereo- And regioselectivity in an intramolecular nitrone-alkene cycloaddition of hept-6-enoses with a trans-acetonide blocking group

Tony Kung Ming Shing, Wai F. Wong, Taketo Ikeno, Tohru Yamada

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12 Citations (Scopus)

Abstract

The positional effect of the trans-acetonide blocking group and the effect of the stereochemistry of the substituents on the regio- and stereoselectivity in intramolecular nitrone-alkene cycloaddition (INAC) reactions of hept-6-enoses are reported. Hept-6-enoses with a 2,3-trans-acetonide group were reacted with N-alkyl hydroxyl-amine to give a mixture of exo and endo cycloadducts (cyclohexanols and cycloheptanols, respectively). Complete formation of endo cycloadducts (cycloheptanols) was realized for the INAC reaction of hept-6-enoses containing a 3,4-trans-O-isopropylidene ring. Similarly, reaction of a hept-6-enose possessing a 4,5-trans-acetonide group surprisingly afforded exo cycloadducts (cyclohexanols) exclusively. The regio-and stereochemical outcomes of these reactions were rationalized on the basis of transition-state energies obtained by computation.

Original languageEnglish
Pages (from-to)2693-2707
Number of pages15
JournalChemistry - A European Journal
Volume15
Issue number11
DOIs
Publication statusPublished - 2009 Mar 2

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Keywords

  • Alkenes
  • Carbohydrates
  • Cycloaddition
  • Cycloheptanes
  • Nitrones

ASJC Scopus subject areas

  • Chemistry(all)

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