Asymmetric hetero Diels-Alder reaction catalyzed by chromium complexes of heterogeneously hybridized salen/salan ligands

Chemistry Letters

Volumn 37, Issue 6, 2008, Pages 632-633

  Eno, Satomi ^a   Egami, Hiromichi ^a   Uchida, Tatsuya ^a   Katsuki, Tsutomu ^a  

^a KYUSHU UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 48249105866     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.2008.632     Document Type: Article

References (23)

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2. b) E. M. McGarrigle, D. G. Gilheany, Chem. Rev. 2005, 105, 1563.
3. c) T. Katsuki, in Comprehensive Coordination Chemistry II, ed. by J. McCleverty, Elsevier Science Ltd., Oxford, 2003, Vol. 9, Chap. 9.4, pp. 207-264.
4. K. Matsumoto, Y. Sawada, B. Saito, K. Sakai, T. Katsuki, Angew. Chem., Int. Ed. 2005, 44, 4935.
5. B. Saito, T. Katsuki, Angew. Chem., Int. Ed. 2005, 44, 4600.
6. K. Matsumoto, B. Saito, T. Katsuki, Chem. Commun. 2007, 3619.
7. H. Fujita, T. Uchida, R. Irie, T. Katsuki, Chem. Lett. 2007, 36, 1092.
8. A. Berkessel, M. Brandenburg, E. Leitterstorf, J. Frey, J. Lex, M. Schäfer, Adv. Synth. Catal. 2007, 349, 2385.
9. For the review on asymmetric HDA reactions, see: a) K. A. Jørgensen, Angew. Chem., Int. Ed. 2000, 39, 3558.
10. b) L. Lin, X. Liu, X. Feng, Synlett 2007, 2147.
11. For asymmetric HDA reactions using Cr(salen) complexes as the catalyst, see: a) S. E. Schaus, J. Brånal, E. N. Jacobsen, J. Org. Chem. 1998, 63, 403.
12. b) K. Aikawa, R. Irie, T. Katsuki, Tetrahedron 2001, 57, 845.
13. c) M. Bandini, P. G. Cozzi, A. UmaniRonchi, Chem. Commun. 2002, 919.
14. d) M. Mellah, B. Ansel, F. Patureau, A. Voituriez, E. Schulz, J. Mol. Catal. A: Chem. 2007, 272, 20.
15. The salalen ligands were synthesized according to the reported procedure: a) B. Saito, H. Egami, T. Katsuki, J. Am. Chem. Soc. 2007, 129, 1978.
16. b) K. Matsumoto, T. Yamaguchi, J. Fujisaki, B. Saito, T. Katsuki, Chem. Asian J. 2008, 3, 351.
17. 2 and the corresponding ligand in a ratio of 1:3; however, it was impossible to separate the complex and the excess ligand and the complexes were used as mixtures.
18. The reaction was carried out with a molar ratio (aldehyde:diene: catalyst = 1:1.8:0.02) on a 0.2 mmol scale. Ee was determined by HPLC analysis (DAICEL CHILALCEL OD-H, hexane/i-PrOH = 9:1). Configuration of the product was determined by comparison of the optical rotations (ref 8a).
19. The reactions in solvents such as ether, acetonitrile, and ethyl acetate proceeded with high enantioselectivity, while those in alcohols, THF, and DMF were sluggish.
20. Typical experimental procedure: To a suspension of 9a (2μmol) and MS 4 Å (30 mg) in toluene (0.5 mL) were added aldehyde (0.10 mmol) and 1-methoxy-3-trimethylsilyloxy-1,3-butadiene (0.18 mmol) at -20 °C under nitrogen. After stirring for 24 h at that temperature, the mixture was treated with TFA and stirred for another 5 min. The mixture was concentrated, and the residue was chromatographed on silica gel to give the corresponding product. Its ee was determined by chiral HPLC analysis.
21. The reaction of benzaldehyde and 1-methoxy-3-trimethyl-silyloxy-1,3- pentadiene (1E,3Z:1E,3E = 3:1) gave the corresponding 5,6-syn product (endo adduct) of 54% ee exclusively in 49% yield.
22. J. Long, J. Hu, X. Shen, B. Ji, K. Ding, J. Am. Chem. Soc. 2002, 124, 10.
23. CCDC No. 681006.