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Keywords:

  • chiral photochemistry;
  • enantiodifferentiating photoisomerization;
  • planar chirality;
  • cyclooctene;
  • cyclic nigerosylnigerose;
  • supramolecular chemistry

ABSTRACT

Isophthalic and terephthalic acid monoesters of cyclic nigerosyl-(1→6)-nigerose (CNN), a cyclic tetrasaccharide composed of four d-glucopyranosyl residues connected by alternating α-1,3- and α-1,6-linkages, were synthesized as novel chiral supramolecular sensitizers for enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to planar chiral (E)-isomer (1E). Despite the saucer-shaped shallow cavity of CNN that does not immediately guarantee strong ground-state interactions with 1Z, the sensitizer-appended CNNs afforded optically active 1E in such enantiomeric excesses that are much improved than those obtained with an α-cyclodextrin analog and comparable with those obtained with a β-cyclodextrin analog. Interestingly, the enantiomeric excess values obtained were a critical function of temperature and solvent to show an inversion of the product chirality by changing the environmental variants. Nevertheless, all of the differential activation parameters calculated from the temperature-dependent enantiomeric excesses gave an excellent compensatory enthalpy–entropy relationship, indicating an operation of a single enantiodifferentiating mechanism in the present chiral photosensitization with modified CNNs. Chirality 24:921–927, 2012. © 2012 Wiley Periodicals, Inc.

Featured Compounds

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  1. 1 - 6
Compound 1Z
Molecular Weight:110.1968
Molecular Formula:C8H14
InChIKey:URYYVOIYTNXXBN-UPHRSURJSA-N
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Compound R-(-)-1E
Molecular Weight:110.1968
Molecular Formula:C8H14
InChIKey:URYYVOIYTNXXBN-OWOJBTEDSA-N
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Compound S-(+)-1E
Molecular Weight:110.1968
Molecular Formula:C8H14
InChIKey:URYYVOIYTNXXBN-OWOJBTEDSA-N
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Compound 2
Molecular Weight:796.678
Molecular Formula:C32H44O23
InChIKey:DSIKQWQNEOVDIJ-JLBZFHOGSA-N
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Compound 3
Molecular Weight:796.678
Molecular Formula:C32H44O23
InChIKey:YFBISOMQYAGYAP-JLBZFHOGSA-N
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Compound 2.1Z
Molecular Weight:906.8747
Molecular Formula:C40H58O23
InChIKey:QZBXWKWROYGFOF-YOJASSQMSA-N
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