Concentration effect on the stereoselectivity of [4+2] cycloaddition reactions of 3-cyano-γ-benzopyrone derivatives with electron rich dienes

Heterocycles

Volumn 48, Issue 3, 1998, Pages 421-425

  Hsung, Richard P ^a  

^a University of Minnesota   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000390816     PISSN: 03855414     EISSN: None     Source Type: Journal    
DOI: 10.3987/com-97-8064     Document Type: Article

References (20)

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2. For biological activities of arisugacin see: F. Kuno, K. Otoguro, K. Shiomi, Y. Iwai, and S. Õmura, J. Antibiotics, 1996, 49, 742;
3. F. Kuno, K. Shiomi, K. Otoguro, T. Sunazuka, and S. Õmura, J. Antibiotics, 1996, 49, 748.
4. A. Alzheimer, Gesamte Psychiatrie, 1907, 64, 1264.
5. Arisugacin's therapeutic potential was found based upon the cholinergic hypothesis since it is a potent inhibitor of acctylcholinesterase (AChE). For leading references see: J. C. Jaén, V. E. Gregor, C. Lee, R. Davis, and M. Emmerling, Bioorganic & Med. Chem. Lett., 1996, 6, 737;
6. V. John, I. Lieberburg, and E. D. Thorsett, 'Annual Report in Medicinal Chemistry,' Vol. 28, Academic Press, INC., Orlando, 1993, p. 197;
7. J. T. Coyle, D. L. Price, and M. R. DeLong, Science, 1983, 219, 1184.
8. R. P. Hsung, J. Org. Chem., 1997, 62, 7904.
9. For a classical example of temperature effect on stereoselectivities of [4+2] cycloaddition reactions see: J. A. Berson, Z. Hamlet, and W. A. Mueller, J. Am. Chem. Soc., 1962, 84, 297.
10. For 3-acylchromones see: a) P. J. Cremins, S. T. Saengchantara, and T. W. Wallace, Tetrahedron, 1987, 13, 3075;
11. K. Ohkata, T. Kubo, K. Miyamoto, M. Ono, J. Yamamoto, and K. Akiba, Heterocycles, 1994, 38, 1483;
12. For an example of 3-acylchromone appearing to function as a dienophile in a dimerization process see: C. K. Ghosh, A. Bhattacharyya, and C. Bandyopadhyay, J. Chem. Soc., Chem. Commun., 1984, 1319.
13. For other acyl-γ-pyrones see: P. W. Groundwater, D. E. Hibbs, M. B. Hursthouse, and M. Nyerges, J. Chem. Soc., Perkin Trans. 1, 1997, 163;
14. P. W. Groundwater, D. E. Hibbs, M. B. Hursthouse, and M. Nyerges, Heterocycles, 1996, 43, 745. Another example of cycloaddition reactions involving 4-H-pyran-4-one derivatives appeared during the course of our study.
15. See: D. Chen and N. I. Totah, Abstract No. ORGN-173, 213th ACS National Meeting, San Francisco, CA, 1997.
16. 3-Cyano-4H-benzopyran-4-thione was reported to give xanthione upon reacting with 1-dimethylamino-1,3-butadiene. An initial [4+2] cycloadduct, albeit never isolated, was postulated as the intermediate involved in providing xanthione after dehydroamination and dehydrocyanation. See: B. Sain, D. Prajapati, A. R. Mahajan, and J. S. Sandhu, Bull. Soc. Chim. Fr., 1994, 131, 313.
17. NOe enhancement was observed only for the tertiary allylic hydrogen on the newly formed ring upon irradiation of the β-hydrogen on the γ-pyrone ring in endo-7. On the other hand, nOe enhancement was observed only for methyl hydrogens upon irradiation of the same β-hydrogen in exo-7.
18. Reaction concentrations of γ-benzopyrone derivatives were maintained at 0.1 M by adjusting the amount of the γ-benzopyrone used to the increased volume caused by the addition of excess of diene. Specifically, for reactions using 17 eq of the diene, 0.12 mmol of 9 and 11 were used to maintain the concentration at 0.1 M since volume increased by 0.2 mL when 17 eq of the diene were added. For reactions using 29 eq of the diene, 0.14 mmol of 9 and 11 were used to maintain the concentration of the γ-benzopyrone at 0.1 M since the reaction volume increased by 0.4 mL when 29 eq of the diene were added.
19. For some examples of concentration effects on stereoselectivity of intermolecular Diels-Alder reactions that were carried out in the presence of aqueous media see: P. A. Grieco, P. Garner, and Z.-M. He, Tetrahedron Lett., 1983, 24, 1897;
20. R. Breslow, U. Maitra, and D. Rideout, Tetrahedron Lett., 1983, 24, 1901.