Immobilization of heterobimetallic multifunctional asymmetric catalyst

Organic Letters

Volumn 2, Issue 26, 2000, Pages 4261-4263

  Arai, Takayoshi ^a   Hu, Qiao Sheng ^b   Zheng, Xiao Fan ^b   Pu, Lin ^b   Sasai, Hiroaki ^a  

^a OSAKA UNIVERSITY   (Japan)

^b UNIVERSITY OF VIRGINIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000841765     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol006837g     Document Type: Article

References (14)

1. Shibasaki, M.; Sasai, H.; Arai, T. Angew. Chem., Int. Ed. Engl. 1997, 36, 1236-1256.
2. Arai, T.; Sasai, H.; Aoe, K.; Okamura, K.; Date, T.; Shibasaki, M. Angew. Chem., Int. Ed. Engl. 1996, 35, 104-106.
3. (a) Hu, Q.-S.; Zheng, X.-F.; Pu, L. J. Org. Chem. 1996, 61, 5200-5201.
4. (b) Hu, Q.-S.; Huang, W.-S.; Vitharana, D.; Zheng, X.-F.; Pu, L. J. Am. Chem. Soc. 1997, 119, 12454-12464.
5. For reviews, see: (c) Pu, L. Chem. Rev. 1998, 98, 2405-2494.
6. (d) Pu, L. Chem. Eur. J. 1999, 5, 2227-2232.
7. 4 (1.9 mg, 0.05 mmol) at 0 °C. After being stirred for 12 h at room temperature, the resulting suspension was directly used as a poly-ALB catalyst.
8. 4 and 1b on the Michael reaction of 3 with 4 after 24 h at room temperature is as follows: 1:1 (67% yield, 32% ee), 1:2 (49%, 87% ee), 1:3 (19% yield, 89% ee).
9. (a) Arai, T.; Yamada, Y. M. A.; Yamamoto, N.; Sasai, H.; Shibasaki, M. Chem. Eur. J. 1996, 2, 1368-1372.
10. (b) Arai, T.; Sasai, H.; Yamaguchi, K.; Shibasaki, M. J. Am. Chem. Soc. 1998, 120, 441-442.
11. Preparation of poly-ALB-II catalyst (2b-II): To a suspension of poly-ALB catalyst (2b) (0.05 mmol as a monomeric catalyst) in THF was added a solution of BuLi (28 μL, 0.045 mmol) in hexane at 0 °C. After being stirred for 1 h at room temperature, the resulting suspension was directly used as a poly-ALB-II catalyst.
12. 2, 25% acetone/hexane) gave the Michael adduct 5 (165 mg, 87%) in 93% ee. After the residue was dried under reduced pressure, poly-(R)-ALB-II (2b-H) (60 mg, quant.) was recovered and reused to the next reaction.
13. Recently reported immobilized catalysts for asymmetric Michael reactions: (a) Kim, Y. S.; Matsunaga, S.; Das, J.; Sekine, A.; Ohshima, T.; Shibasaki, M. J. Am. Chem. Soc. 2000, 122, 6506-6507.
14. (b) Matsunaga, S.; Ohshima, T.; Shibasaki, M. Tetrahedron Lett. 2000, 41, 8473-8478.