Pathways for stereoinformation transfer: Enhanced enantioselectivity via diastereomeric recycling of organolithium/(-)-sparteine complexes

Journal of Organic Chemistry

Volumn 61, Issue 17, 1996, Pages 5718-5719

  Basu, Amit ^a   Gallagher, Donald J ^a   Beak, Peter ^a  

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

Author keywords

[No Author keywords available]

Indexed keywords

ANILINE DERIVATIVE;

ARTICLE; CATALYSIS; COMPLEX FORMATION; DRUG SYNTHESIS; ENANTIOMER; REACTION ANALYSIS; STEREOCHEMISTRY; TECHNIQUE;

EID: 0029798146     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo961123y     Document Type: Article

References (19)

1. (a) Park, Y. S.; Boys, M. L.; Beak, P. J. Am. Chem. Soc. 1998, 118, 3757 and references cited therein. (b) Basu, A.; Beak, P. J. Am. Chem. Soc. 1996, 118, 1575.
2. (a) Park, Y. S.; Boys, M. L.; Beak, P. J. Am. Chem. Soc. 1998, 118, 3757 and references cited therein. (b) Basu, A.; Beak, P. J. Am. Chem. Soc. 1996, 118, 1575.
3. Muci, A. R.; Campos, K. R.; Evans, D. A. J. Am. Chem. Soc. 1995, 117, 9075. Tsukazaki, M.; Tinkl, M.; Roglans, A.; Chapell, B. J.; Taylor, N. J.; Snieckus, V. J. Am. Chem. Soc. 1996, 118, 685.
4. Muci, A. R.; Campos, K. R.; Evans, D. A. J. Am. Chem. Soc. 1995, 117, 9075. Tsukazaki, M.; Tinkl, M.; Roglans, A.; Chapell, B. J.; Taylor, N. J.; Snieckus, V. J. Am. Chem. Soc. 1996, 118, 685.
5. Beak, P.; Basu, A.; Gallagher, D. J.; Park, Y. S.; Thayumanavan, S. Acc. Chem. Res. Submitted for publication. Beak, P.; Du, H. J. Am. Chem. Soc. 1993, 115, 2516.
6. Beak, P.; Basu, A.; Gallagher, D. J.; Park, Y. S.; Thayumanavan, S. Acc. Chem. Res. Submitted for publication. Beak, P.; Du, H. J. Am. Chem. Soc. 1993, 115, 2516.
7. (a) Hirsch, R.; Hoffmann, R. W. Chem. Ber. 1992, 125, 975.
8. (b) Hoffmann, R. W.; Julius, M.; Chemla, F.; Ruhland, T.; Frenzen, G. Tetrahedron 1994, 50, 6049.
9. Klute, W.; Dress, R.; Hoffmann, R. W. J. Chem. Soc., Perkin Trans. 2 1993, 1409.
10. Seeman, J. I. Chem. Rev. 1983, 83, 83.
11. When a racemic organometallic reagent is treated with a deficiency of a ehiral electrophile, the product ratio obtained can be different than the ratio obtained with excess electrophile. This forms the basis for Hoffmann's test of configurational stability. See ref 4a and Hayashi, T.; Konishi, M.; Okamoto, Y.; Kabeta, K.; Kumada, M. J. Org. Chem. 1986, 51, 3772. Gately and Norton have recently reported a study of equilibrating diastereomeric zirconium organometallic species in which product enantiomeric ratios increase as the equivalent of electrophile is increased from 2-fold excess to 60 equiv: Gately, D. A.; Norton, J. R. J. Am. Chem. Soc. 1996, 118, 3479 and references cited therein. This is shown by kinetic analyses to be a consequence of the reaction with the electrophile becoming competitive with the rate of epimerization of the diastereomeric complexes.
12. When a racemic organometallic reagent is treated with a deficiency of a ehiral electrophile, the product ratio obtained can be different than the ratio obtained with excess electrophile. This forms the basis for Hoffmann's test of configurational stability. See ref 4a and Hayashi, T.; Konishi, M.; Okamoto, Y.; Kabeta, K.; Kumada, M. J. Org. Chem. 1986, 51, 3772. Gately and Norton have recently reported a study of equilibrating diastereomeric zirconium organometallic species in which product enantiomeric ratios increase as the equivalent of electrophile is increased from 2-fold excess to 60 equiv: Gately, D. A.; Norton, J. R. J. Am. Chem. Soc. 1996, 118, 3479 and references cited therein. This is shown by kinetic analyses to be a consequence of the reaction with the electrophile becoming competitive with the rate of epimerization of the diastereomeric complexes.
13. This a case of kinetic quenching, or boundary condition I in ref 6.
14. ‡ in both reactions. This is a Curtin-Hammett situation, or boundary condition II in ref 6. A limitation of this test is that it can establish only configurational stability but not configurational lability. If the two experiments provide the same enantiomeric ratio, this can arise either as a result of configurational lability or accidental equivalence of the activation energies of configurationally stable complexes (see text).
15. A correction of 0.09 kcal/mol has been incorporated to account for the observation of an er of 56:44 under the conditions of an experiment that should provide an er of 50:50.
16. In general, the maximum error on all er values, as derived from chiral stationary phase HPLC anaylsis, is ±2%. The agreement of the experimental and predicted er values thus falls within our expected range of experimental error.
17. This assumption does not affect the calculations or conclusions derived from our analysis.
18. Noyori, R.; Tokunaga, M.; Kitamura, M. Bull. Chem. Soc. Jpn. 1995, 68, 36.
19. Hoffmann and co-workers have recently reported a kinetic resolution of the enantiomers of a configurationally stable α-seleno Grignard reagent. The use of a deficient amount of a chiral electrophile enriches the reaction solution in one enantiomer, which is then reacted with an achiral electrophile. Klute, W.; Krüger, M.; Hoffmann, R. W. Chem. Ber. 1996, 129, 633.