Highly enantioselective Friedel-Crafts alkylations of pyrroles and indoles with α′-hydroxy enones under Cu(II)-simple bis(oxazoline) catalysis

Journal of the American Chemical Society

Volumn 127, Issue 12, 2005, Pages 4154-4155

  Palomo, Claudio ^a   Oiarbide, Mikel ^a   Kardak, Bharat G ^a   García, Jesús M ^a,b   Linden, Anthony ^a,c  

^a UNIVERSITY OF THE BASQUE COUNTRY UPV EHU   (Spain)

^b PUBLIC UNIVERSITY OF NAVARRE   (Spain)

^c UNIVERSITY OF ZURICH   (Switzerland)

Author keywords

[No Author keywords available]

Indexed keywords

ALKENE DERIVATIVE; ALPHA' HYDROXY ENONE DERIVATIVE; COPPER DERIVATIVE; INDOLE DERIVATIVE; OXAZOLINE DERIVATIVE; PYRROLE DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; CATALYSIS; CHEMICAL BOND; CHEMICAL STRUCTURE; CHIRALITY; ENANTIOSELECTIVITY; FRIEDEL CRAFTS REACTION; REACTION ANALYSIS; STEREOCHEMISTRY; STRUCTURE ANALYSIS; SYNTHESIS;

EID: 16244408623     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0423217     Document Type: Article

References (29)

1. Olah, G. A.; Kishnamurti, R.; Prakash, G. K. S. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 3, pp 293-339.
2. For a review, see: (a) Bandini, M.; Melloni, A.; Umani-Ronchi, A. Angew. Chem., Int. Ed. 2004, 43, 550-556. See also:
3. (b) Jørgensen, K. A. Synthesis 2003, 1117-1125.
4. (a) Paras, N. A.; MacMillan, D. W. C. J. Am. Chem. Soc. 2001, 123, 4370-4371.
5. (b) Austin, J. F.; MacMillan, D. W. C. J. Am. Chem. Soc. 2002, 124, 1172-1173.
6. (c) Paras, N. A.; MacMillan, D. W. C. J. Am. Chem. Soc. 2002, 124, 7894-7895.
7. Jensen, K. B.; Thorhauge, J.; Mazell, R.-G.; Jørgensen, K. A. Angew. Chem., Int. Ed. 2001, 40, 160-163.
8. (a) Zhuang, W.; Hausen, T.; Jørgensen, K. A. Chem. Commun. 2001, 347-348.
9. (b) Zhou, J.; Tang, Y. J. Am. Chem. Soc. 2002, 124, 9030-9031.
10. (c) Zhou, J.; Tang, Y. Chem. Commun. 2004, 432-433.
11. (d) Zhou, J.; Ye, M.-C.; Huang, Z.-Z.; Tang, Y. J. Org. Chem. 2004, 69, 1309-1320.
12. Evans, D. A.; Scheidt, K. A.; Frandrick, K. R.; Lam, H. W.; Wu, J. J. Am. Chem. Soc. 2003, 125, 10780-10781.
13. (a) Bandini, M.; Fagioli, P.; Garavelli, M.; Melloni, A.; Trigari, V.; Umani-Ronchi, A. J. Org. Chem. 2004, 69, 7511-7518.
14. (b) Bandini, M.; Melloni, A.; Tommasi, S.; Umani-Ronchi, A. Helv. Chim. Acta 2003, 86, 3753-3763.
15. Widely used, chelating N-enoyl-2-oxazolidinones in combination with Cu-(II)-BOX catalysts seemed to be totally ineffective; for example, unaltered starting materials are recovered after 2 days of stirring a mixture of N-methyl pyrrole and N-crotonyl-2-oxazolidinone in the presence of 10 mol % Cu(II)-t-BOX catalyst.
16. Palomo, C.; Oiarbide, M.; García, J. M.; González, A.; Arceo, E. J. Am. Chem. Soc. 2003, 125, 13942-13943.
17. Palomo, C.; Oiarbide, M.; Halder, R.; Kelso, M.; Gómez-Bengoa, E.; García, J. M. J. Am. Chem. Soc. 2004, 126, 9188-9189.
18. Hypothetically, the 1,4-metal arrangement resulting from the coordination of templates 2 and 4 with the catalyst is advantageous over the 1,5-metal arrangement encountered in other typical bidentate templates, such as 3. Also, see ref 8.
19. (a) Sundberg, R. D. Pyrroles and Their Benzo Derivatives: Synthesis and Applications. In Comprehensive Heterocyclic Chemistry; Katrizky, A. R., Rees, C. W., Eds.; Pergamon: Oxford/1984, Vol. 4, pp 313-376.
20. (b) Saxton, J. E. Nat. Prod. Rep. 1997, 14, 559-590.
21. (c) Toyota, M.; Ihara, N. Nat. Prod. Rep. 1998, 15, 327-340.
22. 2O, or toluene, tested using catalyst 12 led to slightly lower selectivity, while the reaction did not proceed at all in acetonitrile. See the Supporting Information for details.
23. Enone/yield of dialkylated 8: 7b/4%, 7d/14%, 7f/8% (See S1 for details).
24. For enhancement of enantiomeric excess by ligand distortion, see: (a) Denmark, S. E.; Stiff, C. M. J. Org. Chem. 2000, 65, 5875-5878.
25. (b) Lipkowitz, K. B.; Schefzick, S.; Avnir, D. J. Am. Chem. Soc. 2001, 123, 6710-6711.
26. Under the conditions reported, no reaction was observed between enone 7a and other types of arenes tested, such as anisole and 3-dimethylaminoanisole.
27. (a) Johnson, J. S.; Evans, D. A. Acc. Chem. Res. 2000, 33, 325-335 and references therein.
28. (b) Thorhauge, J.; Roberson, M.; Hazell, R. G.; Jørgensen, K. A. Chem.-Eur. J. 2002, 8, 1888-1898.
29. For assessment of the enantiomeric purity and the absolute configuration of the products, see the Supporting Information.