Effects of lithium salts on the enantioselectivity of protonation of enolates with chiral imide

Synlett

Volumn , Issue 2, 1998, Pages 174-176

  Yanagisawa, Akira ^a   Kikuchi, Tetsuo ^a   Yamamoto, Hisashi ^a  

^a NAGOYA UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000143068     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1998-1594     Document Type: Article

References (23)

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3. (c) Yanagisawa, A.; Ishihara, K.; Yamamoto, H. Synlett 1997, 411.
4. (d) Yanagisawa, A.; Watanabe, T.; Kikuchi, T.; Kuribayashi, T.; Yamamoto, H. Synlett 1997, 956.
5. Reviews of asymmetric protonations: (a) Duhamel, L.; Duhamel, P.; Launay, J.-C.; Plaquevent, J.-C. Bull. Soc. Chim. Fr. 1984, II-421.
6. (b) Fehr, C. Chimia 1991, 45, 253.
7. (c) Waldmann, H. Nachr. Chem., Tech. Lab. 1991, 39, 413.
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9. (e) Fehr, C. Angew. Chem. Int. Ed. Engl. 1996, 35, 2566.
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11. (b) Henderson, K. W.; Dorigo, A. E.; Liu, Q.-Y.; Williard, P. G.; Schleyer, P. v. R.; Bernstein, P. R. J. Am. Chem. Soc. 1996, 118, 1339.
12. Protonation: (a) Yasukata, T.; Koga, K. Tetrahedron: Asymmetry 1993, 4, 35.
13. (b) Gerlach, U.; Haubenreich, T.; Hünig, S. Chem. Ber. 1994, 127, 1981. Alkylation:
14. (c) Murakata, M.; Nakajima, M.; Koga, K. J. Chem. Soc., Chem. Commun. 1990, 1657.
15. (d) Hasegawa, Y.; Kawasaki, H.; Koga, K. Tetrahedron Lett. 1993, 34, 1963.
16. (e) Imai, M.; Hagihara, A.; Kawasaki, H.; Manabe, K.; Koga, K. J. Am. Chem. Soc. 1994, 116, 8829.
17. 3N). Selective 1,4-reduction by L-Selectride®, see: Fortunato, J. M.; Ganem, B. J. Org. Chem. 1976, 41, 2194.
18. n-BuLi can be used for cleavage of the Si-O bond of silyl enol ether 4 instead of MeLi. Generation of lithium enolates: Colvin, E. W. Silicon in Organic Synthesis; Butterworth: London, 1981; p 217.
19. The absolute configuration of 6 was determined by comparison of its optical rotation with published data: Ohta, T.; Miyake, T.; Seido, N.; Kumobayashi, H.; Akutagawa, S.; Takaya, H. Tetrahedron Lett. 1992, 33, 635.
20. A small amount of hexane (ca. 6%) was also contained in each solvent. Hünig and coworkers have reported a similar solvent effect, see reference 4b.
21. 3N, HMPA): Krafft, M. E.; Holton, R. A. Tetrahedron Lett. 1983, 24, 1345.
22. Abu-Hasanayn, F.; Streitwieser, A. J. Am. Chem. Soc. 1996, 118, 8136.
23. 3OH).