New chiral bis(diphenylphospholane) ligands: Design, synthesis, and application to catalytic enantioselective aldol reaction to ketones

Tetrahedron Letters

Volumn 46, Issue 25, 2005, Pages 4325-4329

  Oisaki, Kounosuke ^a   Zhao, Dongbo ^a   Suto, Yutaka ^a   Kanai, Motomu ^a,b   Shibasaki, Masakatsu ^a  

^a UNIVERSITY OF TOKYO   (Japan)

^b JAPAN SCIENCE AND TECHNOLOGY AGENCY   (Japan)

Author keywords

Aldol reaction; Asymmetric catalysis; Chiral phospholane; Chiral tertiary alcohol; Ketones

Indexed keywords

CARBON; COPPER; CYCLOPROPANE DERIVATIVE; FLUORINE; HYDROXIDE; KETONE; LIGAND; METAL;

ALDOL REACTION; ARTICLE; CATALYSIS; CATALYST; CHELATION; CHEMICAL BOND; CHEMICAL STRUCTURE; CHIRALITY; ENANTIOSELECTIVITY; REACTION ANALYSIS; SYNTHESIS;

EID: 19444371103     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2005.04.084     Document Type: Article

References (32)

1. D.J. Ramón, and M. Yus Angew. Chem., Int. Ed. 43 2004 284 287
2. E.J. Corey, and A. Guzmán-Pérez Angew. Chem., Int. Ed. 37 1998 388 415
3. For practical examples, see: Y. Hamashima, M. Kanai, and M. Shibasaki J. Am. Chem. Soc. 122 2000 7412 7413
4. K. Yabu, S. Masumoto, S. Yamasaki, Y. Hamashima, M. Kanai, W. Du, D.P. Curran, and M. Shibasaki J. Am. Chem. Soc. 123 2001 9908 9909
5. S.-K. Tian, and L. Deng J. Am. Chem. Soc. 123 2001 6195 6196
6. S.-K. Tian, and L. Deng J. Am. Chem. Soc. 125 2003 9900 9901
7. H. Deng, M.P. Isler, M.L. Snapper, and A.H. Hoveyda Angew. Chem., Int. Ed. 41 2002 1009 1012 For other examples, see references cited therein
8. For practical examples, see: C. García, L.K. LaRochelle, and P.J. Walsh J. Am. Chem. Soc. 124 2002 10970 10971
9. M. Yus, D.J. Ramon, and O. Prieto Tetrahedron: Asymmetry 14 2003 1103 1114
10. S.-J. Jeon, and P.J. Walsh J. Am. Chem. Soc. 125 2003 9544 9545
11. H. Li, and P.J. Walsh J. Am. Chem. Soc. 126 2004 6538 6539
12. J.M. Betancort, C. García, and P.J. Walsh Synlett 2004 749 760 For other examples, see references cited therein
13. For a practical example, see: R. Wada, K. Oisaki, M. Kanai, and M. Shibasaki J. Am. Chem. Soc. 126 2004 8910 8911 For other examples, see references cited therein
14. S.E. Denmark, and Y. Fan J. Am. Chem. Soc. 124 2002 4233 4235
15. K. Oisaki, Y. Suto, M. Kanai, and M. Shibasaki J. Am. Chem. Soc. 125 2003 5644 5645
16. For metal fluoride-catalyzed asymmetric aldol reactions to aldehydes, see: J. Krüger, and E.M. Carreira J. Am. Chem. Soc. 120 1998 867 868
17. B.L. Pagenkopf, J. Krüger, A. Stojanovic, and E.M. Carreira Angew. Chem., Int. Ed. 37 1998 3124 3126
18. A. Yanagisawa, Y. Nakatsuka, K. Asakawa, H. Kageyama, and H. Yamamoto Synlett 2001 69 72
19. A. Yanagisawa, Y. Nakatsuka, K. Asakawa, M. Wadamoto, H. Kageyama, and H. Yamamoto Bull. Chem. Soc. Jpn. 74 2001 1477 1484
20. M. Wadamoto, N. Ozasa, A. Yanagisawa, and H. Yamamoto J. Org. Chem. 68 2003 5593 5601
21. The following experimental results support these ideas. (1) The enantioselectivity was independent of the alkoxide substituents of the silicon atom. Both ketene triethoxysilyl acetal and ketene trimethoxysilyl acetal produced the same enantioselectivity, which suggested that the silicon is not relevant to the enantio-differentiation step (aldol addition to substrate ketones). (2) The order dependencies of the initial reaction rate on [ketone], [catalyst], and [silyl enolate] were determined to be 0, 1.5, and -0.8, respectively, which indicated that the addition step is not the rate-determining step (see Ref. 6)
22. Chiral amine ligands such as pybox and salen, and monophosphines such as MOP and Feringa's phosphoramidite produced only very low reactivity and/or no enantioselectivity
23. Both E- and Z-silyl enolates produced the syn-isomer with low diastereoselectivity (syn:anti = 1.6:1), which suggested a linear transition state (see Ref. 6)
24. F. Guillen, and J.-C. Fiaud Tetrahedron Lett. 40 1999 2939 2942
25. F. Guillen, M. Rivard, M. Toffano, J.-Y. Legros, J.-C. Daran, and J.-C. Fiaud Tetrahedron 58 2002 5895 5904
26. C.J. Pilkington, and A. Zanotti-Gerosa Org. Lett. 5 2003 1273 1275
27. There was no significant difference in reactivity between catalysts coordinated by a monodentate phosphine and a bidentate phosphine
28. 3·2EtOH and 5l. Therefore, the competitive coordination of triphenylphosphine to generate achiral CuF was negligible when 5l was used as a chiral ligand
29. 3) δ: 12.0 (s)
30. 4, filtration, concentration, and purification by silica gel column chromatography (AcOEt/hexane) gave the aldol product
31. The previous best result for aliphatic ketones was only 35% ee from 4-phenylbutan-2-one in Denmark's catalysis
32. Other ketene silyl acetals than 2 can be utilized for the present catalytic enantioselective aldol reaction to ketones. The enantio-induction at the α-position was much more efficient (up to 90% ee was obtained using tol-BINAP; unpublished result) than the tertiary alcohol construction at the β-position. See Ref. 6 for preliminary results of this type of asymmetric reaction