Ligand effects in the organolithium-mediated enantioselective α-deprotonation of achiral epoxides

Tetrahedron Asymmetry

Volumn 8, Issue 14, 1997, Pages 2303-2306

  Hodgson, David M ^a   Lee, Gary P ^a  

^a UNIVERSITY OF OXFORD   (United Kingdom)

Author keywords

[No Author keywords available]

Indexed keywords

EPOXIDE; LIGAND; LITHIUM DERIVATIVE; ORGANIC COMPOUND; SPARTEINE;

ARTICLE; CHEMICAL REACTION; PRIORITY JOURNAL; REACTION ANALYSIS; STEREOCHEMISTRY; TECHNIQUE;

EID: 0030796218     PISSN: 09574166     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0957-4166(97)00262-0     Document Type: Article

References (19)

1. (a) Hodgson, D. M.; Lee, G. P. Chem. Commun. 1996, 1015-1016;
2. (b) Review: Hodgson, D. M.; Gibbs, A. R.; Lee, G. P. Tetrahedron 1996, 52, 14361-14384.
3. (+)-Sparteine can be obtained, for example, by reduction of (-)-lupanine (2-oxosparteine) obtained by resolution of the racemate obtained from Lupinus albus L. (Ebner, T.; Eichelbaum, M.; Fischer, P.; Meese, C. O. Arch. Pharm. (Weinheim) 1989, 322, 399-403).
4. For some exceptions see: Beak, P.; Bass, A.; Gallagher, D. J.; Park, Y. S.; Thayumanavan, S. Acc. Chem. Res. 1996, 29, 552-560.
5. Gallagher, D. J.; Wu, S.; Nikolic, N. A.; Beak, P. J. Org. Chem. 1995, 60, 8184-8154.
6. 2 symmetry and asymmetric induction see: Whitesell, J. K. Chem. Rev. 1989, 89, 1581-1590.
7. Denmark, S. E.; Nakajima, N.; Nicaise, O. J.-C.; Faucher, A.-M.; Edwards, J. P. J. Org. Chem. 1995, 60, 4884-4892.
8. (a) Denmark, S. E.; Nakajima, N.; Nicaise, O. J.-C. J. Am. Chem. Soc. 1994, 116, 8797-8798;
9. (b) Review: Denmark, S. E.; Nicaise, O. J.-C. Chem. Commun. 1996, 999-1004.
10. 7 bisoxazoline ligands 4a-c gave the same sense of asymmetric induction as (-)-sparteine 2.
11. The reaction mixtures were maintained at -78°C or -98°C for 5 h following addition of the epoxide and then warmed slowly to ambient temperature overnight. For the general experimental protocol followed see reference 1a.
12. 1H NMR analysis].
13. 1a
14. Zschage, O.; Hoppe, D. Tetrahedron 1992, 48, 5657-5666.
15. Kang, J.; Cho, W. O.; Cho, H. G.; Oh, H. J. Bull. Korean Chem. Soc. 1994, 15, 732-739.
16. Kang, J.; Cho, W. O.; Cho, H. G. Tetrahedron: Asymmetry 1994, 5, 1347-1352; Kang, J.; Kim, J. I.; Lee, J. H. Bull. Korean Chem. Soc. 1994, 15, 865-868.
17. Kang, J.; Cho, W. O.; Cho, H. G. Tetrahedron: Asymmetry 1994, 5, 1347-1352; Kang, J.; Kim, J. I.; Lee, J. H. Bull. Korean Chem. Soc. 1994, 15, 865-868.
18. Galinovsky, G.; Knoth, P.; Fischer, W. Monatsh. Chem. 1955, 86, 1014-1023.
19. 1a [75%, 36% conversion to (-)-alcohol 3 was observed after 10 min (following complete addition of the epoxide 1)]. There was no change in the ee of (-)-alcohol 3 during the course of the latter reaction suggesting that the gradual generation of the lithium alkoxide of (-)-alcohol 3 does not influence the asymmetric induction (chiral alkoxides can effect enantioselective deprotonations: Amadji, M.; Vadecard, J.; Plaquevent, J.-C.; Duhamel, L.; Duhamel, P. J. Am. Chem. Soc. 1996, 118, 12483-12484, and references cited therein).