Copper(II)-catalyzed exo and enantioselective cycloadditions of azomethine imines

Organic Letters

Volumn 10, Issue 14, 2008, Pages 2971-2974

  Sibi, Mukund P ^a   Rane, Digamber ^a   Stanley, Levi M ^a   Soeta, Takahiro ^a  

^a NORTH DAKOTA STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 57649136151     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol800904t     Document Type: Article

References (30)

1. For a comprehensive review of 1,3-dipolar cycloadditions, see: (a) Synthetic Applications of 1,3-Dipolar Cycloaddition Chemistry toward Heterocycles and Natural Products; Padwa, A., Pearson, W. H., Eds.; John Wiley and Sons: Hoboken, NJ, 2003.
2. For a recent review on asymmetric 1,3-dipolar cycloadditions, see: (b) Pellissier, H. Tetrahedron 2007, 63, 3235.
3. For a highlight on enantioselective cycloadditions of azomethine ylides, see: (a) Nájera, C.; Sansano, J. M. Angew. Chem., Int. Ed. 2005, 44, 6272.
4. For selected recent examples of enantioselective cycloadditions of nitrones, see: (b) Evans, D. A.; Song, H.-J.; Fandrick, K. R. Org. Lett. 2006, 8, 3351.
5. (c) Kano, T.; Hashimoto, T.; Maruoka, K. J. Am. Chem. Soc. 2005, 127, 11926.
6. For selected recent examples of enantioselective cycloadditions of azomethine imines, see: (d) Chen, W.; Du, W.; Duan, Y.-Z.; Wu, Y.; Yang, S.-Y.; Chen, Y.-C. Angew. Chem., Int. Ed. 2007, 46, 7667.
7. (e) Suga, H.; Funyu, A.; Kakehi, A. Org. Lett. 2007, 9, 97.
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10. For enantioselective cycloaddition of nitrile oxides, see: (a) Sibi, M. P.; Itoh, K.; Jasperse, C. P. J. Am. Chem. Soc. 2004, 126, 5366.
11. For enantioselective cycloaddition of nitrile imines, see: (b) Sibi, M. P.; Stanley, L. M.; Jasperse, C. P. J. Am. Chem. Soc. 2005, 127, 8276.
12. For enantioselective cycloadditions of diazoalkanes and diazoacetates, see: (a) Kanemasa, S.; Kanai, T. J. Am. Chem. Soc. 2000, 122, 10710.
13. (b) Kano, T.; Hashimoto, T.; Maruoka, K. J. Am. Chem. Soc. 2006, 128, 2174.
14. (c) Sibi, M. P.; Stanley, L. M.; Soeta, T. Org. Lett. 2007, 9, 1553.
15. For selected endo and enantioselective azomethine ylide cycloadditions, see: (a) Zeng, W.; Chen, G.-Y.; Zhou, Y.-G.; Li, Y.-X. J. Am. Chem. Soc. 2007, 129, 750.
16. (b) Zhang, X.; Wang, B.; Longmire, J. M. J. Am. Chem. Soc. 2002, 124, 13400.
17. For selected exo and enantioselective azomethine ylide cycloadditions, see: (c) Yan, X.-X.; Peng, Q.; Zhang, Y.; Zhang, K.; Hong, W.; Hou, X.-L.; Wu, Y.-D. Angew. Chem., Int. Ed. 2006, 45, 1979.
18. (d) Llamas, T.; Arrayás, R. G.; Carretero, J. C. Org. Lett. 2006, 8, 1795.
19. (a) Kanemasa, S.; Oderaotoshi, Y.; Tanaka, J.; Wada, E. J. Am. Chem. Soc. 1998, 120, 12355.
20. (b) Kobayashi, S.; Kawamura, M. J. Am. Chem. Soc. 1998, 120, 5840.
21. For exo and enantioselective nitrone cycloadditions, see: (a) Sibi, M. P.; Ma, Z.; Jasperse, C. P. J. Am. Chem. Soc. 2004, 126, 718.
22. (b) Suga, H.; Nakajima, T.; Itoh, K.; Kakehi, A. Org. Lett. 2005, 7, 1431.
23. (c) Desimoni, G.; Faita, G.; Mella, M. Boiocchi, M. Eur. J. Org. Chem. 2005, 1020.
24. For an example of exo and enantioselective azomethine imine cycloaddition, see: Chen, W.; Yuan, X.-H.; Li, R.; Du, W.; Wu, Y.; Ding, L.-S.; Chen, Y.-C. Adv. Synth. Catal. 2006, 348, 1818.
25. 2 as the Lewis acid led to 91% yield of 3a and 4a as a 90:10 exo/endo mixture with 98% ee for the exo adduct 3a.
26. (a) Sibi, M. P.; Venkatraman, L.; Liu, M.; Jasperse, C. P. J. Am. Chem. Soc. 2001, 123, 8444.
27. (b) Sibi, M. P.; Stanley, L. M.; Nie, X.; Venkatraman, L.; Liu, M.; Jasperse, C. P. J. Am. Chem. Soc. 2007, 129, 395.
28. The 4 Å MS lead to increased reactivity by preventing adventitious water molecules from binding to the Lewis acid, the enhanced diastereoselectivity in the absence of 4 Å MS may result from cycloaddition onto a chiral copper complex with a copper-bound water molecule.
29. See the Supporting Information for details and a crystal structure of 3i. NOE experiments demonstrated that the exo cycloadduct was the major diastereomer.
30. The opposite enantiomer of ligand 5 was used for the exo-selective nitrone cycloadditions in reference 7a.