Ir-catalyzed functionalization of 2-substituted indoles at the 7-position: Nitrogen-directed aromatic borylation

Journal of the American Chemical Society

Volumn 128, Issue 49, 2006, Pages 15552-15553

  Paul, Sulagna ^a   Chotana, Ghayoor A ^a   Holmes, Daniel ^a   Reichle, Rebecca C ^a   Maleczka Jr , Robert E ^a   Smith III, Milton R ^a  

^a MICHIGAN STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

BORON DERIVATIVE; INDOLE DERIVATIVE; IRIDIUM; NITROGEN;

ARTICLE; CATALYSIS; CATALYST; CHEMICAL ANALYSIS; CHEMICAL REACTION; STEREOCHEMISTRY; SYNTHESIS;

BORON COMPOUNDS; CATALYSIS; DEUTERIUM; HETEROCYCLIC COMPOUNDS; HYDROCARBONS, AROMATIC; INDOLES; MOLECULAR STRUCTURE; NITROGEN; ORGANOMETALLIC COMPOUNDS;

EID: 33845457554     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0631652     Document Type: Article

References (31)

1. (a) Sundberg, R. J. In Comprehensive Heterocyclic Chemistry; Katritzky, A. R., Rees, C. W., Eds.; Pergamon Press: Oxford, 1984; Vol. 4, pp 314-476.
2. (b) Jones, R. A. In Comprehensive Heterocyclic Chemistry, Katritzky, A. R., Rees, C. W., Eds.; Pergamon Press: Oxford, 1984; Vol. 4, pp 201-312.
3. (a) Deprez, N. R.; Kalyani, D.; Krause, A.; Sanford, M. S. J. Am. Chem. Soc. 2006, 128, 4972-4973.
4. (b) Lane, B. S.; Brown, M. A.; Sames, D. J. Am. Chem. Soc. 2005, 127, 8050-8057.
5. (c) Wang, X.; Lane, B. S.; Sames, D. J. Am. Chem. Soc. 2005, 127, 4996-4997.
6. (d) Ishiyama, T.; Nobuta, Y.; Hartwig, J. F.; Miyaura, N. Chem. Commun. 2003, 2924-2925.
7. (e) Takagi, J.; Sato, K.; Hartwig, J. F.; Ishiyama, T.; Miyaura, N. Tetrahedron Lett. 2002, 43, 5649-5651.
8. (f) Ishiyama, T.; Takagi, J.; Hartwig, J. F.; Miyaura, N. Angew. Chem., Int. Ed. 2002, 41, 3056-3058.
9. (a) Govek, S. P.; Overman, L. E. J. Am. Chem. Soc. 2001, 123, 9468-9469.
10. (b) Deng, H. B.; Jung, J. K.; Liu, T.; Kuntz, K. W.; Snapper, M. L.; Hoveyda, A. H. J. Am. Chem. Soc. 2003, 125, 9032-9034.
11. (c) Nicolaou, K. C.; Chen, D. Y. K.; Huang, X. H.; Ling, T. T.; Bella, M.; Snyder, S. A. J. Am. Chem. Soc. 2004, 126, 12888-12896.
12. (d) Garg, N. K.; Sarpong, R.; Stoltz, B. M. J. Am. Chem. Soc. 2002, 124, 13179-13184.
13. (e) Lin, S.; Yang, Z.-Q.; Kwok, B. H. B.; Koldobskiy, M.; Crews, C. M.; Danishefsky, S. J. J. Am. Chem. Soc. 2004, 126, 6347-6355.
14. Aluminum anilide has been reported to mediate ethylene insertion into the C7 C-H bond of 2-methylindole at 280-300 °C: (a) Stroh, R.; Hahn, W. Justus Liebigs Ann. Chem. 1959, 623, 176-183. Low-yielding Rh-catalyzed carbene insertion into the C7 C-H of a 3-substituted indole has been claimed:
15. (b) Kennedy, A. R.; Taday, M. H.; Rainier, J. D. Org. Lett. 2001, 3, 2407-2409.
16. 5b are known: (a) Wiesner, W.; Vanpee, K. H.; Lingens, F. FEBS Lett. 1986, 209, 321-324.
17. (b) Dong, C. J.; Flecks, S.; Unversucht, S.; Haupt, C.; van Pee, K. H.; Naismith, J. H. Science 2005, 309, 2216-2219.
18. (a) Hartung, C. G.; Fecher, A.; Chapell, B.; Snieckus, V. Org. Lett. 2003, 5, 1899-1902.
19. (b) Regioselectivity of this type, previously ascribed to directed ortho metalation, is now attributed to a complex-induced proximity effect (CIPE). See: Whisler, M. C.; MacNeil, S.; Snieckus, V.; Beak, P. Angew. Chem., Int. Ed. 2004, 43, 2206-2225.
20. (a) Tse, M. K.; Cho, J.-Y.; Smith, M. R., III. Org. Lett. 2001, 3, 2831-2833.
21. (b) Cho, J. Y.; Tse, M. K.; Holmes, D.; Maleczka, R. E., Jr.; Smith, M. R., III. Science 2002, 295, 305-308.
22. (a) Ishiyama, T.; Takagi, J.; Ishida, K.; Miyaura, N.; Anastasi, N. R.; Hartwig, J. F. J. Am. Chem. Soc. 2002, 124, 390-391.
23. (b) Boller, T. M.; Murphy, J. M.; Hapke, M.; Ishiyama, T.; Miyaura, N.; Hartwig, J. F. J. Am. Chem. Soc. 2005, 127, 14263-14278.
24. 3 group, affording the 7-borylated indole in 88% yield. See Supporting Information for details.
25. An intriguing alternative to this latter mechanism, involving coordination of the indole N to B in one of the boryl ligands, is not shown.
26. GC-MS indicates 20% of a third isomer. It was not obtained sufficiently pure for assignment of regiochemistry to be made.
27. Chotana, G. A.; Rak, M. A.; Smith, M. R., III. J. Am. Chem. Soc. 2005, 127, 10539-10544.
28. A decrease in selectivity for benzofuran versus indole is consistent with replacing the indole NH with a less basic O in a heteroatom chelation mechanism.
29. 14b (a) Hinman, R. L.; Whipple, E. B. J. Am. Chem. Soc. 1962, 84, 2534-2539.
30. (b) Muir, D. M.; Whiting, M. C. J. Chem. Soc., Perkin Trans. 2 1976, 388-392.
31. Prieto, M.; Zurita, E.; Rosa, E.; Munoz, L.; Lloyd-Williams, P.; Giralt, E. J. Org. Chem. 2004, 69, 6812-6820.