Fully selective intramolecular ortho photocycloaddition of 4-(4-methoxy-phenoxy)-3-(N³-benzoylthymin-1-yl)but-1- ene: an unprecedented benzene–thymine photocycloaddition

Abstract

On irradiation of 4-(4-methoxyphenoxy)-3-(N³-benzoylthymin-1-yl)but-1-e ne 1 at 254 nm in THF a single photoadduct 2 is formed as a result of chemo-, regio- and stereo-selective intramolecular ortho photocycloaddition of the thymine double bond to the 1,2-positions of the phenyl ring.

References

1. J. Cornelisse, Chem. Rev., 1993, 93, 615.
2. D. De Keukeleire, S.-L. He, D. Blakemore and A. Gilbert, J. Photochem. Photobiol. A: Chem., 1994, 80, 233.
3. D. De Keukeleire, S.-L. He and C.-Y. Wang, University of Gent, Faculty of Pharmaceutical Sciences, unpublished results.
4. O. Mitsunobu, Synthesis, 1981, 1.
5. A. A. Lamola, Photochem. Photobiol., 1968, 7, 619; Pure Appl. Chem., 1970, 24, 599; G. J. Fisher and H. E. Johns, Photochemistry and Photobiology of Nucleic Acids, ed. S. Y. Wang, Academic Press, New York, 1976, vol. 1, p. 226.
6. W. Oppolzer and T. Godel, J. Am. Chem. Soc., 1978, 100, 2583; Helv. Chim. Acta, 1984, 67, 1154; T. Umehara, Y. Inouye and H. Kakisawa, Bull. Chem. Soc. Jpn., 1981, 54, 3492; H. Seto, S. Tsunoda, H. Ikeda, Y. Fujimoto, T. Tatsuno and H. Yoshioka, Chem. Pharm. Bull., 1985, 33, 2594; J. D. Winkler, J. P. Hey and F. J. Hannon, Heterocycles, 1986, 25, 55.
7. W. Saeyens, P. Herdewijn and D. De Keukeleire, University of Gent, Faculty of Pharmaceutical Sciences, unpublished results.
8. D. Bryce-Smith, A. Gilbert, B. Orger and H. M. Tyrrell, J. Chem. Soc., Chem. Commun., 1974, 334.
9. B. Sket, N. Zupancic and M. Zupan, Tetrahedron, 1986, 42, 753.
10. H. A. Neijenesch, R. J. P. J. de Ruiter, E. J. Ridderikhoff, J. O. van den Ende, L. J. Laarhoven, L. J. W. van Putten and J. Cornelisse, J. Photochem. Photobiol. A: Chem., 1991, 60, 325.
11. D. C. Blakemore and A. Gilbert, J. Chem. Soc., Perkin Trans. 1, 1992, 18, 2265.
12. M. D. Shetlar, J. Christensen and K. Hom, Photochem. Photobiol., 1984, 39, 125.