Allenyl Enolates - A New Class of Chiral Ambident Nucleophiles, 4 1: Axis to Center Chirality Transfer in Aldol Reactions of Allenyl Enolates

Synlett

Volumn 1996, Issue 1, 1996, Pages 87-88

  Laux, Michael ^a   Krause, Norbert ^a   Koop, Ulrich ^a  

^a UNIVERSITY OF BONN   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0006775226     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1996-5302     Document Type: Article

References (23)

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2. (b) Part 2: N. Krause, S. Arndt, Chem. Ber. 1993, 126, 261-263.
3. (c) Part 3: N. Krause, G. Handke, S. Arndt, M. Laux, GIT Fachz. Lab. 1993, 37, 1010-1011.
4. C.H. Heathcock, Modern Enolate Chemistry: Regio- and Stereoselective Formation of Enolates and the Consequence of Enolate Configuration on Subsequent Reactions, in: Modern Synthetic Methods (R. Scheffold, Ed.), Vol. 6, pp. 1-102, VHCA, Basel, VCH, Weinheim, 1992.
5. (a) N. Krause, Chem. Ber. 1990, 123, 2173-2180.
6. (b) N. Krause, Chem. Ber. 1991, 124, 2633-2635.
7. (c) G. Handke, Ph.D.Thesis, TH Darmstadt, 1993.
8. Due to the presence of the bulky t-butyl group at C-5 of the allenyl enolate 3, reprotonation at C-4 by diisopropylamine does not take place at low temperature. Upon warming up, however, reprotonation gives the conjugated diene ethyl 5,6,6-trimethyl-2,4-heptadienoate (E/Z mixture).
9. Like/unlike nomenclature: D. Seebach, V. Prelog, Angew. Chem. 1982, 94, 696-702; Angew. Chem. Int. Ed. Engl. 1982, 21, 654-656.
10. Like/unlike nomenclature: D. Seebach, V. Prelog, Angew. Chem. 1982, 94, 696-702; Angew. Chem. Int. Ed. Engl. 1982, 21, 654-656.
11. R.A. Gibbs, K. Bartels, R.W.K. Lee, W.H. Okamura, J. Am. Chem. Soc. 1989, 111, 3717-3725.
12. (a) R. Peter, Ph.D.Thesis, Universität Marburg, 1983.
13. (b) D.A. Evans, L.R. McGee, Tetrahedron. Lett. 1980, 21, 3975-3978.
14. N. Krause, G. Handke, Tetrahedron Lett. 1991, 32, 7225-7228.
15. 2 oxidation of the resulting β-hydroxyester rac-6.
16. M.H. Ansari, T. Kusumoto, T. Hiyama, Tetrahedron Lett. 1993, 34, 8271-8274.
17. 4 gave the corresponding enediol which was ketalized with 2,2-dimethoxypropane and ozonized. Comparison with an authentic sample (GC-analysis on LIPODEX E) showed that the (R)-dioxolane was formed, proving that 6 possesses the (R)-configuration.
18. C.J. Elsevier, P. Vermeer, J. Org. Chem. 1989, 54, 3726-3730.
19. Determined by GC-analysis with octakis(2,6-di-O-methyl-3-O-pentyl)-γ-cyclodextrin.
20. 3).
21. 4 gave (2S,3S)-isomer (Comparison with an authentic sample by GC-analysis on LIPODEX E).
22. D. Seebach, J.-M. Lapierre, K. Skobridis, G. Greiveldinger, Angew. Chem. 1994, 106, 457- 458; Angew. Chem. Int. Ed. Engl. 1994, 33, 440-441.
23. D. Seebach, J.-M. Lapierre, K. Skobridis, G. Greiveldinger, Angew. Chem. 1994, 106, 457- 458; Angew. Chem. Int. Ed. Engl. 1994, 33, 440-441.