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Inoue Y, Wada T, Sugahara N, et al. Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins. J Org Chem. 2000;65(23):8041-50doi: 10.1021/jo001262m.
Inoue, Y., Wada, T., Sugahara, N., Yamamoto, K., Kimura, K., Tong, L. H., Gao, X. M., Hou, Z. J., & Liu, Y. (2000). Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins. The Journal of organic chemistry, 65(23), 8041-50. https://doi.org/10.1021/jo001262m
Inoue, et al. "Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins." The Journal of organic chemistry vol. 65,23 (2000): 8041-50. doi: https://doi.org/10.1021/jo001262m
Inoue Y, Wada T, Sugahara N, Yamamoto K, Kimura K, Tong LH, Gao XM, Hou ZJ, Liu Y. Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins. J Org Chem. 2000 Nov 17;65(23):8041-50. doi: 10.1021/jo001262m. PMID: 11073615.
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J Org Chem. 2000 Nov 17;65(23):8041-50. doi: 10.1021/jo001262m.

Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins.

The Journal of organic chemistry

Inoue, Wada, Sugahara, Yamamoto, Kimura, Tong, Gao, Hou, Liu

Affiliations

  1. Department of Molecular Chemistry, Osaka University, 2-1 Yamada-oka, Suita 565-0871, Japan, Inoue Photochirogenesis Project, ERATO, JST, 4-6-3 Kamishinden, Toyonaka 565-0085, Japan, Lanzhou Institute of Chemical Physics, Academia Sinica, Lanzhou 730.

PMID: 11073615 DOI: 10.1021/jo001262m

Abstract

Supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to the chiral (E)-isomer (1E) via inclusion and sensitization by modified alpha-, beta-, and/or gamma-cyclodextrin derivatives, possessing benzoate (2a, 3a, 4a), isomeric phthalates (3b-d), and tethered benzamide (3e) chromophores, has been investigated in aqueous methanol solutions at varying temperatures. The photostationary-state 1E/1Z ratios obtained upon sensitization with 2-4 in 1:1 water-methanol reached 0.4-0.8, which are higher than the value of ca. 0.25 reported for sensitizations by conventional alkyl benzoates in hydrocarbon solvents, although the ratio was reduced to 0.2-0.4 in water or methanol. The sensitizations of 1Z by alpha- and gamma-cyclodextrin benzoates (2a, 4a) with size-mismatched cavities gave 1E of poor enantiomeric excesses (ee's) smaller than 3 and 5%, respectively. In contrast, beta-cyclodextrin derivatives (3a-e) afforded much higher ee's of up to 24%, depending on the solvent composition. Thus, the modification of cyclodextrin with a sensitizing group successfully enhanced the product through the excited-state supramolecular interaction within the cavity. Interestingly, the product ee's obtained with benzoate 3a and methyl phthalate 3b are not a simple function of either temperature or solvent, but are nicely correlated with the host occupancy or the percentage of occupied host. This means that the entropy factor plays an insignificant role in this supramolecular photochirogenesis system, which is in sharp contrast to the decisive role of entropy in the conventional (nonsupramolecular) counterpart performed in homogeneous solutions, where an inversion of product chirality by temperature variation is reported to occur.

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