Synthesis of a bifunctional ligand for the sequential enantioselective catalysis of various reactions

European Journal of Organic Chemistry

Volumn , Issue 6, 2001, Pages 1045-1048

  Annunziata, Rita ^a   Benaglia, Maurizio ^a   Cinquini, Mauro ^a   Cozzi, Franco ^a  

^a UNIVERSITY OF MILAN   (Italy)

Author keywords

Asymmetric catalysis; Bifunctional ligands; Chiral ligands; Cyclopropanations; Dihydroxylations

Indexed keywords

ARTICLE; ENANTIOMER; HYDROXYLATION; PROTON NUCLEAR MAGNETIC RESONANCE; REACTION ANALYSIS; STEREOCHEMISTRY; SYNTHESIS;

EID: 0035080792     PISSN: 1434193X     EISSN: None     Source Type: Journal    
DOI: 10.1002/1099-0690(200103)2001:6<1045::AID-EJOC1045>3.0.CO;2-I     Document Type: Article

References (21)

1. Review: Catalytic Asymmetric Synthesis (Ed.: I. Ojima), VCH Publishers, New York, 1993.
2. Review: A. K. Ghosh, P. Mathivanan, J. Cappiello, Tetrahedron: Asymmetry 1998, 9, 1-45.
3. [4-7]
4. A. P. H. J. Schenning, J. H. Lutje Spelberg, D. H. W. Hubert, M. C. Feiters, R. J. M. Nolte, Chem. Eur. J. 1998, 4, 871-880 (epoxidation of alkenes).
5. M. P. Sibi, G. R. Cook, P. Liu, Tetrahedron Lett. 1999, 40, 2477-2480 (reduction of ketones).
6. Y. Hamashima, M. Kanai, M. Shibasaki, J. Am. Chem. Soc. 2000, 122, 7412-7413 (hydrocyanation of ketones).
7. For the attachment of two identical ligands to a soluble polymer support, see: C. Bolm, C. L. Dinter, A. Seger, H. Höcker, J. Brozio, J. Org. Chem. 1999, 64, 5730-5731.
8. For a recent review on multifunctional asymmetric catalysis, see: M. Shibasaki, Chemtracts - Organic Chemistry 1999, 12, 979-998.
9. Review: D. J. Berrisford, C. Bolm, K. B. Sharpless, Angew. Chem. Int. Ed. Engl. 1995, 34, 1059-1070.
10. L. J. Goosen, H. Liu, K. Ruprecht Dress, K. B. Sharpless, Angew. Chem. Int. Ed. 1999, 38, 1080-1083, and references therein.
11. Review: A. Nelson, Angew. Chem. Int. Ed. 1999, 38, 1583-1585.
12. A. E. Taggi, A. M. Hafez, H. Wack, B. Young, W. H. Drury III, T. Lectka, J. Am. Chem. Soc. 2000, 122, 7831-7832.
13. A modification of a literature procedure has been employed: I. W. Davies, L. Gerena, L. Castonguay, C. H. Senanayake, R. D. Larsen, T. R. Verhoeven, P. J. Reider, Chem. Commun. 1996, 1753-1754.
14. These poor yields can be ascribed to the steric hindrance and relatively low acidity of the trisubstituted bridging carbon atom. The use of stronger bases or higher temperatures for the metalation resulted in extensive decomposition of the bis(oxazoline)s. Reversal of the alkylation sequence (reaction of 4 first with MeI and then with 3) led to only low yields of 1.
15. This reaction was performed as described by: K. B. Sharpless, W. Amberg, M. Beller, H. Chen, Y. Kawanami, D. Lübben, E. Manoury, Y. Ogino, T. Shibata, T. Ukita, J. Org. Chem. 1991, 56, 4585-4588.
16. Under these conditions, the use of DHQD 4-chlorobenzoate as a ligand afforded (R,R)-diol 6 with 99% ee. The use of DHQD acetate (i.e. of an aliphatic ester of DHQD as 1) under different conditions (E. N. Jacobsen, I. Markò, W. S. Mungall, G. Schröder, K. B. Sharpless, J. Am. Chem. Soc. 1988, 110, 1968-1970) gave the product with 94% ee.
17. This reaction was performed with gem-dimethyl 4b as the ligand, as described in: D. A. Evans, K. A. Worpel, M. M. Hinman, M. M. Faul, J. Am. Chem. Soc. 1991, 113, 726-728. Under these conditions, (R,R)-7 was obtained in 56% yield with 99% ce; the trans/cis ratio was 73:27.
18. VI species can indeed decrease the yield of the reaction, most probably by inhibiting the catalytic cycle. This deactivation seems to be less significant in the presence of the Os ligand DHQD.
19. [15]), (R)-8 was obtained with 74% ee.
20. The sequential process was not attempted using a substrate possessing two double bonds, for instance 1,4-divinylbenzene, in order to avoid the possibility of the stereocenters generated in the first reaction "intramolecularly" affecting the stereochemical course of the second reaction. On the contrary, cyclopropane 7 would seem unlikely to exert an "intermolecular" effect on the synthesis of diol 8. Moreover, the use of a substrate with two double bonds could give rise to up to eight stereoisomeric products in the sequential process, thus greatly complicating the stereochemical analysis of the reaction course.
21. D. Beer, R. Meuwly, A. Vasella, Helv. Chim. Acta 1982, 65, 2570-2582.