The cytoskyrin cascade: A facile entry into cytoskyrin A, deoxyrubroskyrin, rugulin, skyrin, and flavoskyrin model systems

Angewandte Chemie - International Edition

Volumn 44, Issue 36, 2005, Pages 5846-5851

  Nicolaou, K C ^a,b   Papageorgiou, Charles D ^a,b   Piper, Jared L ^a,b   Chadha, Raj K ^a,b  

^a SCRIPPS RESEARCH INSTITUTE   (United States)

^b UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

Cascade reactions; Dimerization; Natural products; Radicals; Synthetic methods

Indexed keywords

CATALYSIS; DIMERIZATION; FREE RADICAL POLYMERIZATION; OXIDATION;

CASCADE REACTIONS; NATURAL PRODUCTS; SYNTHETIC METHODS;

ORGANIC COMPOUNDS;

ANTHRAQUINONE DERIVATIVE; CYTOSKYRIN A; FLAVOSKYRIN; NAPHTHOQUINONE; RUGULIN; SKYRIN;

ARTICLE; CHEMICAL STRUCTURE; CHEMISTRY;

ANTHRAQUINONES; MODELS, MOLECULAR; NAPHTHOQUINONES;

EID: 24944591100     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200502011     Document Type: Article

References (25)

1. S. F. Brady, M. P. Singh, J. E. Janso, J. Clardy, Org. Lett. 2000, 2, 4047-4049.
2. In a series of papers that were intriguing hut lacking in details, the Shibata group reported on their investigations in this field, which included both the isolation of and chemical interconversions between some of these natural products and related compounds, see: a) N. Takeda, S. Seo, Y. Ogihara, U. Sankawa, I. Iitaka, I. Kitagawa, S. Shibata. Tetrahedron 1973, 29, 3703-3719;
3. b) Y. Ogihara, N. Kobayashi, S. Shibata, Tetrahedron Lett. 1968, 1881-1886;
4. c) S. Seo, U. Sankawa, S. Shibata, Tetrahedron Lett. 1972, 731-734;
5. d) S. Shibata, Pure Appl. Chem. 1972, 33, 109-127;
6. e) S. Seo, U. Sankawa, Y. Ogihara, Y. Iitaka, S. Shibata, Tetrahedron 1973, 29, 3721-3726;
7. f) D.-M. Yang, U. Sankawa, Y. Ebizuka, S. Shibata, Tetrahedron 1976, 32, 333-335.
8. P. Sedmera, M. Podojil, J. Vokoun, V. Betina, P. Nemec, Folia Microbiol. 1978, 23, 64-67.
9. B. Franck, R. Chahin, H.-G. Eckert, R. Langenberg, V. Radtke, Angew. Chem. 1975, 87, 846-847;
10. Angew. Chem. Int. Ed. Engl. 1975, 14, 819-820.
11. Clardy and co-workers speculated on the biosynthetic origins of cytoskyrin A as following a redox path from monomeric 6-methyl-1,3,8- trihydroxyanthraquinone (emodin, see reference [1]). This type of dimerization had been hinted at earlier by the Shibata group (see reference [2e]).
12. Polysubstituted examples of this cage structure have been described previously: a) J. A. Beisler, J. V. Silverton, A. Penttila, D. H. S. Horn, H. M. Fales, J. Am. Chem. Soc. 1971, 93, 4850-4855;
13. b) K. Hirao, Y. Ohuchi, O. Yonemitsu, J. Chem. Soc. Chem. Commun. 1982, 99-100.
14. F. M. Hauser, S. Chakrapani, W. P. Ellenberger, J. Org. Chem. 1991, 56, 5248-5250.
15. a) D. Momose, K. Iguchi, T. Sugiyama, Y. Yamada, Tetrahedron Lett. 1983, 24, 921-924;
16. b) S. K. Bagal, R. M. Adlington, R. Marquez, A. R. Cowley, J. E. Baldwin, Tetrahedron Lett. 2003, 44, 4993-4996.
17. CCDC-274 275 (4), -274 271 (5), and -274 272 (3) contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
18. The high overall yield for this cascade reflects the higher efficiency by which the final product (1) can be purified by chromatography, as opposed to the intermediate compounds (3 or 2) whose enolic nature makes their isolation more tedious.
19. O. Ermer, Angew. Chem. 1983, 95, 251-252;
20. Angew. Chem. Int. Ed. Engl. 1983, 22, 251-252. We thank Professor Scott Rychnovsky for pointing out this reference to us.
21. 13C NMR data as well as COSY and HMQC correlations, which can be found in the Supporting Information.
22. a) J. D. Dunitz, G. Filippini, A. Gavezzotti, Helv. Chim. Acta 2000, 83, 2317-2335;
23. b) J. D. Dunitz, J. Bernstein, Acc. Chem. Res. 1995, 28, 193-200, and references therein. We thank Professor Jack Dunitz for pointing out these articles to us and for his stimulating comments.
24. [11] and the present examples involve carbon atoms at close proximity to each other, in the former case the X-ray analysis revealed a bond, whereas in the latter case it missed a bond.
25. We thank Professor O. Ermer for suggesting that we revert to this space group (Cc) and for critically reviewing our conclusions regarding this anomalous X-ray crystallographic analysis.