Olefins turned alkylating agents: Diastereoselective intramolecular Zr-catalyzed olefin alkylations

Organic Letters

Volumn 4, Issue 3, 2002, Pages 395-398

  Cesati III, Richard R ^a   De Armas, Judith ^a   Hoveyda, Amir H ^a  

^a BOSTON COLLEGE   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKENE; ALKYLATING AGENT; ZIRCONIUM;

ALKYLATION; ARTICLE; CATALYSIS; CHEMISTRY; STEREOISOMERISM;

ALKENES; ALKYLATING AGENTS; ALKYLATION; CATALYSIS; STEREOISOMERISM; ZIRCONIUM;

EID: 0037034341     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol017090c     Document Type: Article

References (38)

1. For selected examples of diastereoselective Zr-catalyzed olefin alkylations, see: (a) Hoveyda, A. H.; Xu, Z. J. Am. Chem. Soc. 1991, 113, 5079-5080.
2. (b) Hoveyda, A. H.; Morken, J. P.; Houri, A. F.; Xu, Z. J. Am. Chem. Soc. 1992, 114, 6692-6697.
3. (c) Houri, A. F.; Didiuk, M. T.; Xu, Z.; Horan, N. R.; Hoveyda, A. H. J. Am. Chem. Soc. 1993, 115, 6614-6624. For selected examples of Zr-catalyzed enantioselective olefin alkylations, see:
4. (d) Morken, J. P.; Didiuk, M. T.; Hoveyda, A. H. J. Am. Chem. Soc. 1993, 115, 6697-6698.
5. (e) Morken, J. P.; Didiuk, M. T.; Visser, M. S.; Hoveyda, A. H. J. Am. Chem. Soc. 1994, 116, 3123-3124.
6. (f) Visser, M. S.; Heron, N. M.; Didiuk, M. T.; Sagal, J. F.; Hoveyda, A. H. J. Am. Chem. Soc. 1996, 118, 4291-4298.
7. (g) Harrity, J. P. A.; La, D. S.; Cefalo, D. R.; Visser, M. S.; Hoveyda, A. H. J. Am. Chem. Soc. 1998, 120, 2343-2351.
8. (h) Adams, J. A.; Heron, N. M.; Koss, A. M.; Hoveyda, A. H. J. Org. Chem. 1999, 64, 854-860.
9. For reviews on stereoselective alkylations of olefins, see: (a) Hoveyda, A. H.; Heron, N. M. In Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer: Berlin, 1999; pp 431-454.
10. (b) Marek, I. J. Chem. Soc., Perkin Trans. 1 1999, 535-544.
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14. Luchaco-Cullis, C. A.; Mizutani, H.; Murphy, K. E.; Hoveyda, A. H. Angew. Chem., Int. Ed. 2001, 40, 1456-1460.
15. Didiuk, M. T.; Johannes, C. W.; Morken, J. P.; Hoveyda, A. H. J. Am. Chem. Soc. 1995, 117, 7097-7104.
16. For efficient and enantioselective Zr-catalyzed additions of various alkylaluminum reagents to unactivated alkenes, see: (a) Kondakov, D. Y.; Negishi, E. J. Am. Chem. Soc. 1995, 117, 10771-10772.
17. (b) Kondakov, D. Y.; Negishi, E. J. Am. Chem. Soc. 1996, 118, 1577-1578.
18. (c) Kondakov, D. Y.; Wang, S.; Negishi, E. Tetrahedron Lett. 1996, 37, 3803-3806.
19. (d) Wipf, P.; Ribe, S. Org. Lett. 2000, 2, 1713-1716.
20. (e) Wipf, P.; Ribe, S. Org. Lett. 2001, 3, 1503-1505.
21. (a) de Armas, J.; Kolis, S. P.; Hoveyda, A. H. J. Am. Chem. Soc. 2000, 122, 5977-5983.
22. (b) de Armas, J.; Hoveyda, A. H. Org. Lett. 2001, 3, 2097-2100. For a related report, see:
23. (c) Terao, J.; Watanabe, T.; Saito, K.; Kambe, N.; Sonoda, N. Tetrahedron Lett. 1998, 39, 9201-9204.
24. For a recent report on Rh-catalyzed allylation of styrenes, see: Tsukada, N.; Sato, T.; Inoue, Y. Chem. Commun. 2001, 237-238.
25. Reaction of 8 is carried out in the presence of n-BuMgCl, since use of EtMgCl leads to the formation of substantial amounts of unidentified products. In other cases, either of the two Grignard reagents may be used with similar efficiency.
26. The major product (∼50%) is phenol i, formed presumably by generation of the magnesium halide of 11 followed by a β-alkoxide elimination. (Equation Presented)
27. Exocyclic alkenes such as 12 are formed through β-hydride abstraction involving the benzylic H through the dialkylzirconocene intermediate. See refs 8a,b for details.
28. The mechanism for the formation of compounds represented by 13 is not clear at the present time. This may involve catalytic ethylmagnesation of the styrene olefin followed by intramolecular reaction of the resulting benzylic magnesium halide with the neighboring tosylate or bromide.
29. The stereochemical identity of 16 and 18 was established through comparison with previously reported data. See: Troutman, M. V.; Apella, D. H.; Buchwald, S. L. J. Am. Chem. Soc. 1999, 121, 4916-4917.
30. Reactions are less efficient with lower catalyst loadings. As an example, when 15 is treated with 5 mol % of 14 (THF, 55 °C, 14 h), 16 is isolated in 52% yield.
31. For a review of the utility of chiral metallocenes in stereoselective synthesis, see: Hoveyda, A. H.; Morken, J. P. Angew. Chem., Int. Ed. Engl. 1996, 35, 1263-1284.
32. Related studies with enantiomerically pure 14 are in progress.
33. For examples of alkylation of alkylmetals with retention of stereochemistry, see: (a) Jensen, F. R.; Nakamaye, K. L. J. Am. Chem. Soc. 1966, 88, 3437-3438.
34. (b) Hoffman, R. W.; Holzer, B. Chem. Commun. 2001, 491-492.
35. For examples where carbomagnesation products are reacted with various electrophiles (other than oxygen), see ref 8b.
36. 2). Related studies are in progress.
37. For two representative examples, see: (a) Trost, B. M.; Toste, F. D. J. Am. Chem. Soc. 1998, 120, 9074-9075.
38. (b) Sato, K.; Yoshimura, T.; Shindo, M.; Shishido, K. J. Org. Chem. 2001, 66, 309-314.