A cycloaddition-rearrangement approach to the squalestatins

Tetrahedron Letters

Volumn 37, Issue 26, 1996, Pages 4623-4626

  Hodgson, David M ^a,c   Bailey, James M ^a,c   Harrison, Timothy ^b,c  

^a UNIVERSITY OF OXFORD   (United Kingdom)

^b NEUROSCIENCE RESEARCH CENTRE   (United Kingdom)

^c UNIVERSITY OF READING   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

SQUALESTATIN; ZARAGOZIC ACID A;

ARTICLE; CYCLIZATION; HYPERCHOLESTEROLEMIA; MYCOSIS; STEREOCHEMISTRY; SYNTHESIS;

EID: 0030600124     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00893-3     Document Type: Article

References (21)

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2. 2. Reviews: Nicolaou, K. C.; Nadin, A. Angew. Chem. Int. Ed. Engl. in press; Procopiou, P. A.; Watson, N. S. Prog. Med. Chem. 1996, 33, 331-378; Bergstrom, J. D.; Dufresne, C.; Bills, G. F.; Nallin-Omstead, M.; Byrne, K. Annu. Rev. Microbiol. 1995, 49, 607-639.
3. 2. Reviews: Nicolaou, K. C.; Nadin, A. Angew. Chem. Int. Ed. Engl. in press; Procopiou, P. A.; Watson, N. S. Prog. Med. Chem. 1996, 33, 331-378; Bergstrom, J. D.; Dufresne, C.; Bills, G. F.; Nallin-Omstead, M.; Byrne, K. Annu. Rev. Microbiol. 1995, 49, 607-639.
4. 2. Reviews: Nicolaou, K. C.; Nadin, A. Angew. Chem. Int. Ed. Engl. in press; Procopiou, P. A.; Watson, N. S. Prog. Med. Chem. 1996, 33, 331-378; Bergstrom, J. D.; Dufresne, C.; Bills, G. F.; Nallin-Omstead, M.; Byrne, K. Annu. Rev. Microbiol. 1995, 49, 607-639.
5. 3. Padwa, A.; Kulkarni, Y. S.; Zhang, Z. J. Org. Chem. 1990, 55, 4144-4153.
6. 4. A 6,7-dideoxysqualestatin has been isolated, however: Blows, W. M.; Foster, G.; Lane, S. J.; Noble, D.; Piercey, J. E.; Sidebottom, P. J.; Webb, G. J. Antibiot. 1994, 47, 740-754.
7. 5. Hook, J. M. Synth. Commun. 1994, 14, 83-87.
8. 6. Isolated total yields of chromatographically homogeneous, spectroscopically pure products are reported.
9. 7. Full details will be reported at a later date.
10. 8. Koyama, H.; Ball, R. G. and Berger, G. D. Tetrahedron Lett. 1994, 35, 9185-9188.
11. 9. Fleming, I. Frontier Orbitals and Organic Chemical Reactions; Wiley: Chichester. 1976: pp. 86-181.
12. 10. Johnston, B. D.; Oehlschlager, A. C. Can. J. Chem. 1984, 62, 2148-2154.
13. 2.
14. 12. (a) Nicolaou, K. C.; Yue, E. W.; La Greca, S.; Nadin, A.; Yang, Z.; Leresche, J. E.; Tsuri, T.; Naniwa, Y.; De Riccardis, F. Chem. Eur. J. 1995, 1, 467-494;
15. (b) Nicolaou, K. C.; Sorensen, E. J. Classics in Total Synthesis; VCH: Weinheim. 1996: pp. 673-709.
16. 2OBn.
17. 14. Armstrong, A.; Barsanti, P. A. Synlett 1995, 903-906.
18. 15. Equilibration via a (comparatively strained) 2,7-dioxabicyclo[2.2.1]heptane formed from ion 14 is also possible in our system.
19. exo]. These data are inconsistent, however, with equatorial alcohol 12.
20. 17. The change in the major : minor isomer ratio after 1 h and 18 h reported in this earlier study (and inversion at the tertiary centre only) is consistent with the epoxide 9 initially forming a six-membered ring oxonium ion (similar to 14) which then partitions between alcohols 11 and [via a 2,7-dioxabicyclo[2.2.1]heptane (Anderson, W. K.; Veysoglu, T. J. Org. Chem. 1973, 38, 2267-2268)] 13. Alcohols 11 and 13 may prefer to interconvert by a seven-membered ring oxonium ion similar to 15.
21. 18. Caron, S.; McDonald, A. I.; Heathcock, C. H. J. Org. Chem. 1995, 60, 2780-2785.