Dynamic thermodynamic resolution: Solvent effects, mechanism, and an asymmetric 3,4,5-substituted benzazepine synthesis

Organic Letters

Volumn 8, Issue 13, 2006, Pages 2667-2670

  Park, Yong Sun ^a,b   Yum, Eul Kgun ^a,c   Basu, Amit ^a   Beak, Peter ^a  

^a UNIVERSITY OF ILLINOIS AT URBANA CHAMPAIGN   (United States)

^b Konkuk University   (South Korea)

^c Chungnam National University   (South Korea)

Author keywords

[No Author keywords available]

Indexed keywords

BENZAZEPINE DERIVATIVE; LITHIUM; SOLVENT;

ARTICLE; CATALYSIS; CHEMICAL STRUCTURE; CHEMISTRY; SYNTHESIS; THERMODYNAMICS;

BENZAZEPINES; CATALYSIS; LITHIUM; MOLECULAR STRUCTURE; SOLVENTS; THERMODYNAMICS;

EID: 33746120810     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol0604015     Document Type: Article

References (17)

1. (a) Basu, A.; Beak, P. J. Am. Chem. Soc. 1996, 118, 3757.
2. (b) Basu, A.; Gallagher, D. J.; Beak, P. J. Org. Chem. 1996, 61, 5718.
3. (c) Beak, P.; Anderson, D. R.; Curtis, M. D.; Laumer, J. M.; Pippel, D. J.; Weisenburger, G. A. Acc. Chem. Res. 2000, 33, 715.
4. For examples see: (a) Coldham, I.; Dufour, S.; Haxell, T. F. N.; Howard, S.; Vennall, G. P. Angew. Chem., Int. Ed. 2002, 41, 3887.
5. (b) Nakamura, S.; Nakagawa, R.; Watanabe, Y.; Toru, T. J. Am. Chem. Soc. 2000, 122, 11340.
6. (c) Clayden, J.; Mitjans, D.; Youssef, L. H. J. Am. Chem. Soc. 2002, 124, 5266.
7. The absolute configuration is assigned to 2·3 based on analogy to the invertive course established for an analogous reaction. (a) Faibish, N. C.; Park, Y. S.; Lee, S.; Beak, P. J. Am. Chem. Soc. 1997, 119, 11561.
8. (b) Park, Y. S.; Weisenburger, G. A.; Beak, P. J. Am. Chem. Soc. 1997, 119, 10537.
9. (c) Weisenberger, G. A.; Faibish, N. C.; Pippel, D. J.; Beak, P. J. Am. Chem. Soc. 1999, 121, 9522.
10. Wilkinson, J. A.; Rossington, S. B.; Ducki, S.; Leonard, J.; Hussain, N. Tetrahedron: Asymmetry 2004, 15, 3011.
11. When s-BuLi was used for the sequence in MTBE, 4 was obtained in 54% yield with an er of 93:7 as opposed to the 80% yield and er of 73:27 in diethyl ether.
12. Since subsequent work shows the diastereomeric complexes to have similar reactivities toward benzaldehyde, the formation of nonracemic major and minor products in the first two entries is provisionally attributed to an asymmetric deprotonation.
13. Since many DTRs are carried out at low temperatures with solid observable, it is possible that some cases do involve resolution by crystallization. In such cases, the favored crystallized diastereoisomer may redissolve but maintain its structure before reaction with an electrophile.
14. Asymmetric syntheses of 5- and 4,5-substituted 1-benzazepines and 3,4-substituted 1-benzazepin-2-ones have been reported as drug candidates.
15. (a) Matsubara, J.; Kitano, K.; Otsubo, K.; Kawano, Y.; Ohtani, T.; Bando, M.; Kido, M.; Uchida, M.; Tabusa, F. Tetrahedron 2000, 56, 4667.
16. (b) Das, J.; Floyd, D. M.; Kimball, S. D.; Duff, K. J.; Vu, T. C.; Lago, M. W.; Moquim, R. V.; Lee, V. G.; Gougoutas, J. Z.; Malley, M. F.; Moreland, S.; Brittain, R. J.; Hedberg, S. A.; Cucinotta, G. G. J. Med. Chem. 1992, 35, 773.
17. An asymmetric synthesis of 4,5,6- and 3,4,5,6-substituted azepanes by a conjugated addition of an N-Boc allyllithium (-)-sparteine complex and subsequent conversions has been reported recently. Lee, S. J.; Beak, P. J. Am. Chem. Soc. 2006, 128, 2178.