Rate acceleration of anionic oxy-cope rearrangements induced by an additional unsaturation

Organic Letters

Volumn 5, Issue 20, 2003, Pages 3631-3634

  Gentric, Lionel ^a   Hanna, Issam ^a   Huboux, Alexandre ^a   Zaghdoudi, Rachida ^a  

^a LABORATOIRE DE SYNTHÈSE ORGANIQUE   (France)

Author keywords

[No Author keywords available]

Indexed keywords

ANION; DECANE;

ACCELERATION; ADDITION REACTION; ARTICLE; ISOPRENYLATION; MOLECULAR STABILITY; PHASE TRANSITION; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0142106431     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol035283p     Document Type: Article

References (24)

1. Evans, D. A.; Golob, A. M. J. Am. Chem. Soc. 1975, 97, 4765-4766.
2. For a review on anion-assisted sigmatropic rearrangements, see: Wilson, S. Org. React. 1993, 43, 93-250.
3. For reviews, see: Paquette, L. A. Angew. Chem., Int. Ed. Engl. 1990, 29, 609-626. Paquette, L. A. Tetrahedron 1997, 53, 13971-14020.
4. For reviews, see: Paquette, L. A. Angew. Chem., Int. Ed. Engl. 1990, 29, 609-626. Paquette, L. A. Tetrahedron 1997, 53, 13971-14020.
5. (a) Evans, D. A.; Baillargeon, D. J.; Nelson, J. V. J. Am. Chem. Soc. 1978, 100, 2242-2243.
6. (b) Paquette, L. A.; Wang, H.-L.; Zeng, Q.; Shih, T.-L. J. Org. Chem. 1998, 63, 6432-6433.
7. (c) Paquette, L. A.; Reddy, Y. R.; Vayner, G.; Houk, K. N. J. Am. Chem. Soc. 2000, 122, 10788-10794.
8. (a) Gregson, R. P.; Mirrington, R. N. Aust. J. Chem. 1976, 29, 2037-2048.
9. (b) Koreeda, M.; Tanaka, Y.; Schwartz, A. J. Org. Chem. 1980, 45, 1172-1174.
10. 1 that the magnitude of the rate acceleration was directly related to the degree of alkoxide-metal dissociation, with maximum acceleration obtained with a more "naked anion". Thus, under identical conditions, the potassium alkoxide rearranged at a much greater rate than sodium alkoxide.
11. Gentric, L.; Hanna, I.; Ricard, L. Org. Lett. 2003, 5, 1139-1142.
12. Details concerning the preparation of the starting allylic alcohols used in this Letter will be given in due course.
13. Formation of hydroxyketone 10 resulted from in situ over-oxidation of the enolate formed as a result of the oxy-Cope process. See for example: Paquette, L. A.; De Russy, N. T.; Pegg, N. A.; Taylor, R. T.; Zydowsky, T. M. J. Org. Chem. 1989, 54, 4576-4581 and references therein.
14. Satisfactory spectral and analytical data were obtained for all new compounds.
15. Stereochemistry of the isopropenyl group in 16 was ascertained by comparison with 15: catalytic hydrogenation of 16 provided 15 in which the relative configuration of the isopropyl group was determined by X-ray crystallographic analysis.
16. For a similar fragmentation, see ref 5b.
17. For theoretical studies of the effects of vinyl substitution on the Cope rearrangements of 1,5-hexadienes, see: Hrovat, D. A.; Beno, B. R.; Lange, H.; Yoo, H.-Y.; Houk, K. N.; Borden W.; T. J. Am. Chem. Soc. 1999, 121, 10529-10537.
18. (a) Paquette, L. A.; Pierre, F. Cottrel, C. E. J. Am. Chem. Soc. 1987, 109, 5731-5740.
19. (b) Paquette, L. A.; DeRussy, D. T.; Rogers, R. D. Tetrahedron 1988, 44, 3139-3148.
20. For related rearrangements of substituted bicyclo[2.2.2]octadienols to the AB-ring system of taxoids, see: (a) Martin, S. F.; Assercq, J.-M.; Austin, R. E.; Dantanarayama, A. P.; Fishpaugh, J. R.; Gluchowski, C.; Guinn, D. E.; Hartmann, M.; Tanaka, T.; Wagner, R.; White, J. B. Tetrahedron 1995, 51, 3455-3482. (b) Banwell, M. G.; Darmos, P.; McLeod, M. D.; Hockless, D. C. R. Synlett 1998, 897-899.
21. For related rearrangements of substituted bicyclo[2.2.2]octadienols to the AB-ring system of taxoids, see: (a) Martin, S. F.; Assercq, J.-M.; Austin, R. E.; Dantanarayama, A. P.; Fishpaugh, J. R.; Gluchowski, C.; Guinn, D. E.; Hartmann, M.; Tanaka, T.; Wagner, R.; White, J. B. Tetrahedron 1995, 51, 3455-3482. (b) Banwell, M. G.; Darmos, P.; McLeod, M. D.; Hockless, D. C. R. Synlett 1998, 897-899.
22. 1H NMR.
23. To our knowledge, only one example of thermal oxy-Cope rearrangement on isopropyl-substituted bicyclo[2.2.2]octenols has hitherto been reported. See ref 5a. Whereas the (E)-isomer underwent the transposition leading to a β-isopropyl cis-decalone, attempts to synthesize its α-epimer from the (Z)-isomer failed. Under the same conditions, this substrate only afforded aromatic compounds.
24. -1 for 33 and 34, respectively (see Supporting Information).