Remarkable ligand effect on the enantioselectivity of the chiral lanthanum complex-catalyzed asymmetric epoxidation of enones

Tetrahedron Letters

Volumn 39, Issue 40, 1998, Pages 7321-7322

  Daikai, Kazuhiro ^a   Kamaura, Masahiro ^a   Inanaga, Junji ^a  

^a KYUSHU UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

CHALCONE; LANTHANUM; LIGAND; METAL COMPLEX;

ARTICLE; CATALYSIS; CHIRALITY; ENANTIOMER; EPOXIDATION; LIGAND BINDING; REACTION ANALYSIS; STEREOCHEMISTRY; SYNTHESIS;

EID: 0032192283     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(98)01569-X     Document Type: Article

References (9)

1. 1. For a review, see: Shibasaki, M.; Sasai, H.; Arai, T. Angew. Chem., Int. Ed. Engl. 1997, 36, 1236 .
2. 2. Hanamoto, T. ; Furuno, Y.; Sugimoto, Y.; Inanaga, J. Synlett, 1997, 79.
3. 3. Bougauchi, M.; Watanabe, S.; Arai, T.; Sasai, H.; Shibasaki, M. J. Am. Chem. Soc. 1997, 119, 2329.
4. 4. For other recent studies on the asymmetric epoxidation of enones, see: (a) Enders, D.; Zhu, J.; Raabe, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 1725;
5. (b) Kroutil, W.; Mayon, P.; Lasterra-Sánchez, M. E.; Maddrell, S. J.; Roberts, S. M.; Thornton, S. R.; Todd, C. J.; Tüter, M. Chem. Commun. 1996, 845;
6. (c) Elston, C. L.; Jackson, R. F. W.; MacDonald, S. J. F.; Murray, P. J. Angew. Chem., Int. Ed. Engl. 1997, 36, 410 and references cited therein.
7. 5. The amount of MS4A largely influenced the product's ee: 53% ee (with 200 mg) and 66% ee (with 500 mg); cf. entry 1 in Table 1. The use of 1 g of MS4A was found to be enough to reproduce the high ees.
8. 3 (8.0 mg) in THF (1.5 ml) and the mixture was stirred for 1 h, and then a decane solution of TBHP (5M, 0.15 ml) was added. After stirring for 0.5 h, a solution of chalcone (105.4 mg) in THF (1 ml) was added and the whole mixture was stirred at room temperature for 0.5 h.
9. 7. A part of this work was presented at the 74th Meeting of the Chemical Society of Japan, Kyoto, March, 1998 and the 15th Meeting of the Rare Earth Society of Japan, Tokyo, May, 1998.