Catalytic enantioselective amination of enolsilanes using C2-symmetric copper(II) complexes as chiral lewis acids

Organic Letters

Volumn 1, Issue 4, 1999, Pages 595-598

  Evans, David A ^a   Johnson, Douglas S ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

AZIDE; COPPER; DYES, REAGENTS, INDICATORS, MARKERS AND BUFFERS; ORGANOMETALLIC COMPOUND; SILANE DERIVATIVE;

AMINATION; ARTICLE; CATALYSIS; CHEMICAL STRUCTURE; CHEMISTRY; STEREOISOMERISM;

AMINATION; AZIDES; CATALYSIS; COPPER; INDICATORS AND REAGENTS; MODELS, MOLECULAR; ORGANOMETALLIC COMPOUNDS; SILANES; STEREOISOMERISM;

EID: 0033606864     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol990113r     Document Type: Article

References (46)

1. (a) Evans, D. A.; Kozlowski, M. C.; Murry, J. A.; Burgey, C. S.; Connell, B. J. Am. Chem. Soc. 1999, 121, 669-685 and references therein.
2. (b) Evans, D. A.; Johnson, J. S. J. Am. Chem. Soc. 1998, 120, 4895-4896.
3. (c) Evans, D. A.; Olhava, E. J.; Johnson, J. S.; Janey, J. M. Angew. Chem., Int. Ed. Engl. 1998, 37, 3372-3375.
4. (d) Evans, D. A.; Miller, S. J.; Lectka, T. C. J. Am. Chem. Soc. 1993, 115, 7027-7030.
5. For reviews on electrophilic amination. see: (a) Boche, G. In Stereoselective Synthesis; Helmchen, G., Hoffmann, R. W., Mulzer, J., Schaumann, E., Eds.; Thieme: Stuttgart, 1996; Vol. 9, pp 5133-5157.
6. (b) Greek, C.; Genet, J. P. Synlett 1997, 741-748. For diastereoselective aminations of chiral enolates or chiral silylketene acetals, see:
7. (c) Evans, D. A.; Britton, T. C.; Dorow, R. L.; Dellaria, J. F. J. Am. Chem. Soc. 1986, 108, 6395-6397.
8. (d) Evans, D. A.; Britton, T. C.; Dorow, R. L.; Dellaria, J. F. Tetrahedron 1988, 44, 5525-5540.
9. (e) Trimble, L. A.; Vederas, J. C. J. Am. Chem. Soc. 1986, 108, 6397-6399.
10. (f) Gennari, C.; Colombo, L.; Bertolini, G. J. Am. Chem. Soc. 1986, 108, 6394-6395.
11. For diastereoselective animations of enolates with chiral aminating reagents, see: (a) Oppolzer, W.; Tamura, O.; Sundarababu, G.; Signer, M. J. Am. Chem. Soc. 1992, 114, 5900-5902.
12. (b) Harris, J. M.; McDonald, R.; Vederas, J. C. J. Chem. Soc., Perkin Trans. 1, 1996, 2669-2674.
13. For a merged enolization enantioselective animation, see: Evans, D. A.; Nelson, S. G. J. Am. Chem. Soc. 1997, 119, 6452-6453.
14. This functionality is present in a number of biologically important natural products: (a) Ciufolini, M. A.; Xi, N. Chem. Soc. Rev. 1998, 27, 437-445.
15. (b) Schmidt, U.; Braun, C.; Sutoris, H. Synthesis 1996, 223-229. For a ribosome-mediated incorporation of hydrazinophenylalanine into a protein, see:
16. (c) Killian, J. A.; Van Cleve, M. D.; Shayo, Y. F.; Hecht, S. M. J. Am. Chem. Soc. 1998, 720, 3032-3042.
17. Details on the preparation of the azo compounds 3a-c and an X-ray crystal structure of 3c may be found in the Supporting Information.
18. Evans, D. A.; Peterson, G. S.; Johnson, J. S.; Barnes, D. M.; Campos, K. R.; Woerpel, K. A. J. Org. Chem. 1998, 63, 4541-4544.
19. The absolute configuration was proven by X-ray crystallography as well as chemical correlation by conversion to the known oxazolidinone 16 (vide infra).
20. 2 has two open coordination sites so its complex with 3 remains neutral. For a review on ligand accelerated catalysis, see: Berrisford, D. J.; Bolm, C.; Sharpless, K. B. Angew. Chem., Int. Ed. Engl. 1995, 34, 1059-1070.
21. This observation aided the development of two Mukaiyama-Michael reactions: Evans, D. A.; Rovis, T.; Kozlowski, M. C.; Tedrow, J. S. J. Am. Chem. Soc. 1999, 121, 1994-1995.
22. The azo compound decomposes in the presence of catalyst 1 at temperatures above -10 °C.
23. Compound (S)-9 was recrystallized (96% ee) and its absolute configuration was proven by X-ray crystallography.
24. N-Acylpyrroles have been used as acylating agents and, as such, can be regarded as activated carboxylic acid equivalents: (a) Brandange, S.; Rodriguez, B. Acta Chem. Scand. 1987, B41, 740-744.
25. (b) Brandange, S.; Holmgren, E.; Leijonmarck, H.; Rodriguez, B. Acta Chem. Scand. 1995, 49, 922-928.
26. (c) Lee, S. D.; Brook, M. A.; Chan, T. H. Tetrahedron Lett. 1983, 24, 1569-1572. To the best of our knowledge only the silylketene aminal of acetylpyrrole has been previously described:
27. (d) Frick, U.; Simchen, G. Liebigs Ann. Chem. 1987, 839-845.
28. It is best to use the hydrate catalyst of 1 when conducting the reaction at room temperature. Compound 3 appears to be stable in the presence of the hydrate catalyst for about 1 h (THF, 25 °C). Notably, the use of sieves is not required, see: ref 1c.
29. (a) Hall, J. H.; Wojciechowska, M. J. Org. Chem. 1978, 43, 3348-3353.
30. (b) Hall, J. H.; Wojciechowska, M. J. Org. Chem. 1979, 44, 4, 38-41.
31. (c) Leblanc, Y.; Fitzsimmons, B. J.; Springer, J. P.; Rokach, J. J. Am. Chem. Soc. 1989, 111, 2995-3000.
32. An intermediate such as A-1 (L = OTf, THF) was detected by elcctrospray MS (m/z = 807 with correct Cu and Cl isotope pattern).
33. (a) For a summary, see: Boger, D. L. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, 1991; Vol. 5, pp 451-512.
34. (b) Liu, J.; Niwayama, S.; You, Y.; Houk, K. N. J. Org. Chem. 1998, 63, 1064-1073.
35. Burk, M. J.; Allen, J. G. J. Org. Chem. 1997, 62, 7054-7057.
36. 2 (see ref 5a). Grehn, L.; Ragnarsson, U. Synthesis 1998, 1817-1821.
37. (a) Paleo, M. R.; Calaza, M. I.; Sardina, F. J. J. Org. Chem. 1997, 62, 6862-6869.
38. (b) Kano, S.; Yokomatsu, T.; Iwasawa, H.; Shibuya, S. Tetrahedron Lett. 1987, 28, 6331-6334.
39. (c) Fujita, M.; Hiyama, T. J. Org. Chem. 1988, 53, 5415-5421.
40. (a) Leblanc, Y.; Fitzsimmons, B. J. Tetrahedron Lett. 1989, 30, 2889-2892.
41. (b) McClure, C. K.; Mishra, P. K.; Grote, C. W. J. Org. Chem. 1997, 62, 2437-2441.
42. 3).
43. (a) Minato, H.; Takeda, K.; Miura, T.; Kobayashi, M. Chem. Lett. 1977, 1095-1098.
44. (b) Arai, E.; Tokuyama, H.; Linsell, M. S.; Fukuyama, T. Tetrahedron Lett. 1998, 39, 71-74.
45. (c) Myers, A. G.; Gleason, J. L.; Yoon, T.; Kung, D. W. J. Am. Chem. Soc. 1997, 119, 656-673.
46. The methyl ester derived from (R)-9 was identical to the methyl ester prepared from 11a (HPLC, Chiracel AD) confirming the (R) absolute stereochemisty for 11a.