The asymmetric power of chiral ligands determined by competitive asymmetric autocatalysis

Organic Letters

Volumn 6, Issue 10, 2004, Pages 1613-1616

  Lutz, François ^a   Sato, Itaru ^a   Soai, Kenso ^a  

^a TOKYO UNIVERSITY OF SCIENCE   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

LIGAND;

ARTICLE; ASYMMETRIC CATALYSIS; CATALYST; CHIRALITY; ENANTIOSELECTIVITY; QUALITATIVE ANALYSIS; QUANTITATIVE ANALYSIS;

EID: 2542627593     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol049559k     Document Type: Article

References (20)

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2. (b) Catalytic Asymmetric Synthesis, 2nd ed.; Ojima, I., Ed.; Wiley-VCH: New York, 2000.
3. Reviews: (a) Noyori, R.; Kitamura, M. Angew. Chem., Int. Ed. Engl. 1991, 30, 49-69. (b) Soai, K.; Niwa, S. Chem. Rev. 1992, 92, 833-856. (c) Pu, L.; Yu, H.-B. Chem. Rev. 2001, 101, 757-824.
4. Reviews: (a) Noyori, R.; Kitamura, M. Angew. Chem., Int. Ed. Engl. 1991, 30, 49-69. (b) Soai, K.; Niwa, S. Chem. Rev. 1992, 92, 833-856. (c) Pu, L.; Yu, H.-B. Chem. Rev. 2001, 101, 757-824.
5. Reviews: (a) Noyori, R.; Kitamura, M. Angew. Chem., Int. Ed. Engl. 1991, 30, 49-69. (b) Soai, K.; Niwa, S. Chem. Rev. 1992, 92, 833-856. (c) Pu, L.; Yu, H.-B. Chem. Rev. 2001, 101, 757-824.
6. (a) Soai, K.; Yokoyama, S.; Ebihara, K.; Hayasaka, T. Chem. Commun. 1987, 1690-1691.
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8. (c) Soai, K.; Hayase, T.; Takai, K.; Sugiyama, T. J. Org. Chem. 1994, 59, 7908-7909.
9. Enantiopure N,N-dipropylnorephedrine (DPNE) 2a and N,N- dibutylnorephedrine (DBNE) 2b catalyze the enantioselective addition of diisopropylzinc to benzaldehyde to afford products with 92% and 93% ee, with yields of 73% and 72%, respectively. When this reaction was carried out in the presence of 10 mol % of (1S,2R)-DPNE 2a and 10 mol % of (1R,2S)-DBNE 2b, an almost racemic product (<5% ee) was obtained.
10. (a) Soai, K.; Shibata, T.; Morioka, H.; Choji, K. Nature 1995, 378, 767-768.
11. (b) Shibata, T.; Morioka, H.; Hayase, T.; Choji, K.; Soai, K. J. Am. Chem. Soc. 1996, 118, 471-472.
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15. Kitamura, M.; Suga, S.; Niwa, M.; Noyori, R. J. Am. Chem. Soc. 1995, 117, 4832-4842.
16. (a) Zhang, S. Y.; Girard, C.; Kagan, H. B. Tetrahedron: Asymmetry 1995, 6, 2637-2640.
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19. (d) Blackmond, D. G. Acc. Chem. Res. 2000, 33, 402-411.
20. To estimate the error in this critical ratio measurement, asymmetric autocatalysis has been initiated by two competing enantiomers, (1S,2R)-and (1R,2S)-DMNE 2f. As the reaction catalyzed by (1S,2R)-2f and (1R,2S)-2f in a 49:51 ratio and a 51:49 ratio afforded (R)-3 with 74.1% ee and (S)-3 with 73.5% ee, respectively, we estimated that the experimental error relative to the loadings of each ligand is below 2%, and the error in their calculated ratio is below 4%.