Highly enantioselective syntheses of anti homoaldol products by (-)-sparteine-mediated lithiation/transmetalation/substitution of N-Boc allylic amines

Organic Letters

Volumn 2, Issue 17, 2000, Pages 2655-2658

  Whisler, Marna C ^a   Vaillancourt, Louis ^a   Beak, Peter ^a  

^a UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AMINE; DYES, REAGENTS, INDICATORS, MARKERS AND BUFFERS; LITHIUM; SPARTEINE; TITANIUM;

ARTICLE; CHEMISTRY; CONFORMATION; STEREOISOMERISM; SYNTHESIS; X RAY CRYSTALLOGRAPHY;

AMINES; CRYSTALLOGRAPHY, X-RAY; INDICATORS AND REAGENTS; LITHIUM; MOLECULAR CONFORMATION; SPARTEINE; STEREOISOMERISM; TITANIUM;

EID: 0034710503     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol006186o     Document Type: Article

References (26)

1. Hoppe, D. Angew. Chem., Int. Ed. Engl. 1984, 23, 932. For a review of chiral homoenolate equivalents, see: Ahlbrecht, H.; Beyer, U. Synthesis 1999, 365.
2. Hoppe, D. Angew. Chem., Int. Ed. Engl. 1984, 23, 932. For a review of chiral homoenolate equivalents, see: Ahlbrecht, H.; Beyer, U. Synthesis 1999, 365.
3. (a) Weisenburger, G. A.; Beak, P. J. Am. Chem. Soc. 1996, 118, 12218.
4. (b) Weisenburger, G. A.; Faibish, N. C.; Pippel, D. J.; Beak, P. J. Am. Chem. Soc. 1999, 121, 9522.
5. Pippel, D. J.; Weisenburger, G. A.; Faibish, N. C.; Beak, P. J. Am. Chem. Soc., submitted for publication.
6. Hoppe, D.; Lichtenberg, F. Angew. Chem., Int. Ed. Engl. 1984, 23, 239. For reviews, see:
7. (a) Hoppe, D.; Krämer, T.; Schwark, J.-R.; Zschage, O. Pure Appl. Chem. 1990, 62, 1999.
8. (b) Hoppe, D.; Hense, T. Angew. Chem., Int. Ed. Engl. 1997, 36, 2282.
9. (a) van Hülsen, E.; Hoppe, D. Tetrahedron Lett. 1985, 26, 411.
10. (b) Zschage, O.; Schwark, J.-R.; Hoppe, D. Tetrahedron 1992, 48, 5657.
11. (c) Marsch, M.; Harms, K.; Zschage, O.; Hoppe, D.; Boche, G. Angew. Chem., Int. Ed. Engl. 1991, 30, 321.
12. The configuration of the lithiated intermediate of 2 is assigned by analogy to that of 1, which has been established by X-ray crystallography. See: Pippel, D. J.; Weisenburger, G. A.; Wilson, S. R.; Beak, P. Angew. Chem., Int. Ed. Engl. 1998, 37, 2522.
13. D calculations were performed by Gustavo Mouro, David Beratan, and Peter Wipf at the University of Pittsburgh.
14. Grieco, P. A.; Oguri, T., Yokoyama, Y. Tetrahedron Lett. 1978, 18, 419.
15. The crystallographic data for 15 and 18 have been deposited with the Cambridge Crystallographic Data Centre as supplementary publication nos. 145026 and 145027, respectively. Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB2 IEZ, U.K. (fax: (+44) 1223-336033; email: deposit@ccdc.cam.ac.uk).
16. Basha, A.; Lipton, M.; Weinreb, S. M. Tetrahedron Lett. 1977, 48, 4171.
17. These allylmetal reactions are presumed to proceed through six-membered transition states. See: Yamamoto, Y.; Asao, N. Chem. Rev. 1993, 2207.
18. Carstens, A.; Hoppe, D. Tetrahedron 1994, 50, 6097.
19. Hoppe, I.; Marsch, M.; Harms, K.; Boche, G.; Hoppe, D. Angew. Chem., Int. Ed. Engl. 1995, 34, 2158.
20. The absolute configurations of the products obtained by transmetalation with a titanium reagent were determined by O-protection and hydrolysis to the corresponding O-protected aldehyde (vide supra). Comparison of optical rotations was made with aldehydes 11 and 12, whose absolute configuration was determined by X-ray crystal analysis of derivatives 15 and 18.
21. A possible origin of the E and Z selectivites may be as described by Hoffmann et al. See: Hoffmann, R. W.; Landmann, B. Chem. Ber. 1986, 119, 1039 for a discussion on the E/Z selectivities observed upon addition of allylboronates to aldehydes.
22. Zschage, O.; Schwark, J.-R.; Hoppe, D. Angew. Chem., Int. Ed. Engl. 1990, 29, 296.
23. See: ref 13 and Krämer, T.; Hoppe, D. Tetrahedron 1987, 28, 5149.
24. (a) Krämer, T.; Schwark, J.-R.; Hoppe, D. Tetrahedron Lett. 1989, 30, 7037.
25. (b) Zschage, O.; Schwark, J.-R.; Krämer, T.; Hoppe, D. Tetrahedron 1992, 48, 8377.
26. (c) Paulsen, H.; Graeve, C; Hoppe, D. Synthesis 1996, 141.