Stereocontrolled synthesis of the key intermediate for the enantioselective synthesis of clerodane natural products

Tetrahedron Letters

Volumn 38, Issue 39, 1997, Pages 6845-6848

  Kato, Michiharu ^a   Kosugi, Hiroshi ^a   Kodaira, Ariko ^a   Hagiwara, Hisahiro ^a   Vogler, Bernhard ^b  

^a TOHOKU UNIVERSITY   (Japan)

^b UNIVERSITY OF HOHENHEIM   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

2 DECALONE; CLERODANE DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; CIS TRANS ISOMERISM; DRUG SYNTHESIS; ENANTIOMER; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030825630     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)01614-6     Document Type: Article

References (16)

1. (a) Merritt, A. T.; Ley, S. V. Natural Product Reports 1992, 9, 243-287.
2. (b) Tokoroyama, T. Journal of Synthetic Organic Chemistry (Japan) 1993, 51, 1164-1177 and references cited therein.
3. Rogers, D.; Unal, G. G.; Williams, D. J.; Ley, S. V.; Sim, G. A.; Joshi, B. S.; Ravindranath, K. R. J. Chem. Soc. Chem. Commun. 1979, 97-98.
4. Kato, M.; Watanabe, M.; Vogler, B.; Awen, B. Z.; Masuda, Y.; Tooyama, Y.; Yoshikoshi, A. J. Org. Chem. 1991, 56, 7071-7076.
5. (Related syntheses) (a) Kato, M.; Kido, F.; Watanabe, M.; Masuda, Y.; Awen, B. Z. J. Chem. Soc. Perkin Trans. 1 1993, 2831-2836.
6. (b) Kato, M.; Kido, F.; Masuda, Y.; Watanabe, M. J. Chem. Soc. Chem. Commun. 1992, 697-698.
7. Thomas A. F.; Bessiere, Y. The Synthesis of Monoterpens in The Total Synthesis of Natural products, ApSimon, J. Ed., John Wiley & Sons, 1988, Vol. 7; pp. 275-454.
8. Watanabe, M.; Awen, B. Z.; Kato, M. J. Org. Chem. 1993, 58, 3923-3927.
9. For the related synthesis, see Kato, M.; Watanabe, M.; Masuda, Y. Bull. Chem. Soc. Jpn. 1992, 65, 2071-2075.
10. 1H NMR, IR, and elementary analytical data.
11. Kato, M.; Kamat, V. P.; Tooyama, Y.; Yoshikoshi, A. J. Org. Chem. 1989, 54, 1536-1538.
12. Snider, B. B.:The Prins and Carbonyl Ene Reactions in Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I. Eds., Pergamon Press, 1991,Vol. 2, pp. 527-561.
13. 2); δ 0.80 (d, J=6.8 Hz, 3H), 0.80 (s, 3H), 0.85 (d, J=6.8 Hz, 3H), 0.90 (s, 3H), 1.41-1.52 (m, 2H), 1.57-1.65 (m, 2H), 1.79 (q, J=6.8 Hz, 1H), 1.87 (dd, J=10.0, 2.4 Hz, 1H), 2.18 and 2.42 (d, J=11.7 Hz, 1H each), 2.41 (q, J=6.8 Hz, 1H), 3.78-4.00 (m, 4H), 4.94 (d, J=17.3 Hz, 1H), 5.14 (d, J=10.8 Hz, 1H), 5.62 (dd, J=17.3, 10.8 Hz, 1H).
14. Cain D. Alkylations of Enols and Enolates in Comprehensive Organic Synthesis, Trost, B. M.; Fleming, I. Eds.; Pergamon Press, 1991, Vol. 3, pp. 1-63.
15. In the structures 21a, the principal NOE correlations are shown. The molecular mechanics calculations (CAChe system/MM2 force field) of 21a indicated the conformer having a boat form in the B-ring is more stable by 0.56 kcal/mol than that having a chair form. Details will be reported elsewhere.
16. Starting with 14, preparation of another key intermediate ii has been performed in a synthetically satisfactory overall yield via the enone i according to the present synthetic route with a slight modification. (equation presented)