Subscribe to RSS
DOI: 10.1055/s-2001-15062
Self-Sensitized Diastereodifferentiating Z-E Photoisomerization of 3-, 4-, and 5-Benzoyloxycyclooctenes: Intra- versus Intermolecular Photosensitization [1]
Publication History
Publication Date:
24 September 2004 (online)
![](https://www.thieme-connect.de/media/synthesis/200108/lookinside/thumbnails/10.1055-s-2001-15062-1.jpg)
Abstract
Upon irradiation at 254 nm, (Z)-3-, 4-, and 5-benzoyloxycyclooctenes (1Z-3Z) efficiently isomerized through intra- and/or intermolecular sensitization to the corresponding diastereomeric E-isomers (1E-3E) with low to moderate diastereomeric excesses (de’s) of up to 43 %. The major diastereomer produced from 1Z was switched from (1R*,3R*)-1E (26 % de) to (1R*,3S*)-1E (-11 % de) by simply increasing the substrate concentration from 1 mM to 50 mM. This unusual switching of product chirality is attributed to the opposite diastereoselectivities for intra- and intermolecular photosensitization. In contrast, 2Z and 3Z did not show such switching behavior, but consistently gave a single diastereomer of up to 9 % and 43 % de, respectively, over a wide range of substrate concentrations (0.04-50 mM), for which totally different mechanisms are responsible. Thus, the intra- and intermolecular sensitizations of 2Z exhibit the same diastereoselectivity, while only the intermolecular sensitization of 3Z can occur as a result of the hindered intramolecular approach of the benzoate substituent to the cyclooctene moiety.
Keywords
cyclooctene - diastereoselectivity - isomerization - photochemistry - self-sensitization
- 1 Preliminary report:
Inoue T.Matsuyama K.Inoue Y. J. Am. Chem. Soc. 1999, 121: 9877 - 2
Rau H. Chem. Rev. 1983, 83: 535 - 3
Inoue Y. Chem. Rev. 1992, 92: 741 - 4
Pete J.-P. Adv. Photochem. 1996, 21: 135 - 5
Everitt SRL.Inoue Y. In Organic Molecular PhotochemistryRamamurthy V.Schanze KS. Marcel Dekker; New York: 1999. p.71-130 - 6
Inoue Y.Wada T.Asaoka S.Sato H.Pete J.-P. Chem. Commun. 2000, 251 - 8
Hayashi T.Tomioka K.Yonemitsu O. Asymmetric Synthesis: Graphical Abstracts and Experimental Methods Kodansha/Gordon & Breach; Tokyo/Amsterdam: 1998. - 9
Gawley RE.Aubè J. In Principles of Asymmetric SynthesisBaldwin JE.Magnus FRS.Magnus PD. Pergamon; Oxford: 1996. - 10
Ager DJ.East MB. Asymmetric Synthetic Methodology CRC Press; Boca Raton: 1996. - 11
Seyden-Penne J. Chiral Auxiliaries and Ligands in Asymmetric Synthesis Wiley; New York: 1995. - 12
Nógrádi M. Stereoselective Synthesis 2nd ed: VCH; Weinheim: 1995. - 13
Noyori R. Asymmetric Catalysis in Organic Synthesis Wiley; New York: 1994. - 14
Wong CH.Whitesides GM. Enzymes in Synthetic Organic Chemistry Pergamon; Oxford: 1994. - 15
Collins AN.Sheldrake GN.Crosby J. Chirality in Industry Vol. 1/Vol. 2: Wiley; Chichester: 1992/1997. - 16
Sheldon RA. Chirotechnology-Industrial Synthesis of Optically Active Compounds Marcel Dekker; New York: 1993. - 17
Inoue Y.Yokoyama T.Yamasaki N.Tai A. J. Am. Chem. Soc. 1989, 111: 6480 - 18
Inoue Y.Yamasaki N.Yokoyama T.Tai A. J. Org. Chem. 1992, 57: 1332 - 19
Inoue Y.Yamasaki N.Yokoyama T.Tai A. J. Org. Chem. 1993, 58: 1011 -
20a
Tsuneishi H.Hakushi T.Tai A.Inoue Y. J. Chem. Soc., Perkin Trans 2 1995, 2057 -
20b
Inoue Y.Tsuneishi H.Hakushi T.Tai A. J. Am. Chem. Soc. 1997, 119: 472 - 21
Hoffmann R.Inoue Y. J. Am. Chem. Soc. 1999, 121: 10702 -
22a
Asaoka S.Ooi M.Jiang P.Wada T.Inoue Y. J. Chem. Soc., Perkin Trans. 2 2000, 77 -
22b
Asaoka S.Horiguchi H.Wada T.Inoue Y. J. Chem. Soc., Perkin Trans. 2 2000, 737 - 23
Asaoka S.Kitazawa T.Wada T.Inoue Y. J. Am. Chem. Soc. 1999, 121: 8486 - 24
Inoue Y.Matsushima E.Wada T. J. Am. Chem. Soc. 1998, 120: 10687 - 25
Inoue Y.Ikeda H.Kaneda M.Sumimura T.Everitt SRL.Wada T. J. Am. Chem. Soc. 2000, 122: 406 - 26 We have reported a similar intramolecular photosensitized diastereodifferentiating isomerization of 1-alkoxymethyl-cyclooctene derivatives tethered to a benzenecarboxylate chromophore with an enantiopure pentane-2,4-diyl bridge. Possessing a long flexible tether, these cyclooctenes efficiently undergo the intramolecular photosensitization to give the corresponding diastereomeric Z-isomers in high photostationary-state Z/E ratios of up to 0.8 for the benzoate derivative at 25 °C and moderate diastereomeric excesses of up to 44 % for the terephthalate derivative at -65 °C:
Sugimura T.Shimizu H.Umemoto S.Tsuneishi H.Hakushi T.Inoue Y.Tai A. Chem. Lett. 1998, 323 - 28
Yamasaki N.Inoue Y.Yokoyama T.Tai A.Ishida A.Takamuku S. J. Am. Chem. Soc. 1991, 113: 1933 - 29
Tsuneishi H.Hakushi T.Inoue Y. J. Chem. Soc., Perkin Trans. 2 1996, 1601 - 30
Whitham GH.Wright M. J. Chem. Soc. (C) 1971, 883 - 32
Koltun WL. Biopolymers 1965, 3: 665 - 33
Inoue Y.Takamuku S.Kunitomi Y.Sakurai H. J. Chem. Soc., Perkin Trans. 2 1980, 1672 - 34
Cope AC.Estes LL. J. Am. Chem. Soc. 1950, 72: 1129 - 35
Crandall JK.Banks DB.Colyer RA.Watkins RJ.Arrington JP. J. Org. Chem. 1968, 33: 423 - 36
Hatchard CG.Parker CA. Proc. R. Soc. London, Ser. A 1956, 235A: 518 - 37
Vesley GF. Mol. Photochem. 1971, 3: 193
References
Inoue Y., Sugahara N., Wada T.; Pure Appl. Chem.; in press
27The asterisk represents the relative configuration of the two stereogenic centers
31We reported the opposite configuration in our previous paper, [1] which is erroneous and should be corrected