Enantioselective Radical Addition to N-Acyl Hydrazones Mediated by Chiral Lewis Acids

Angewandte Chemie - International Edition

Volumn 42, Issue 41, 2003, Pages 5061-5063

  Friestad, Gregory K ^a   Shen, Yuehai ^a   Ruggles, Erik L ^a  

^a UNIVERSITY OF VERMONT   (United States)

Author keywords

Amines; Asymmetric catalysis; Enantioselectivity; Hydrazones; Radical reactions

Indexed keywords

ADDITION REACTIONS; CATALYSIS; CHEMICAL BONDS; COMPLEXATION; FREE RADICALS; NITROGEN COMPOUNDS; STEREOCHEMISTRY;

ENANTIOSELECTIVITY;

MOLECULAR ORIENTATION;

AMINE; HYDRAZONE DERIVATIVE; LEWIS ACID; RADICAL;

ADDITION REACTION; ARTICLE; CATALYSIS; CATALYST; CHEMICAL BOND; CHIRALITY; ENANTIOSELECTIVITY; LIGAND BINDING; RADICAL REACTION; SYNTHESIS;

EID: 0242323495     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200352104     Document Type: Article

References (43)

1. For reviews of basic principles and applications of radical reactions, see Radicals in Organic Synthesis (Eds.: M. P. Sibi, P. Renaud), Wiley-VCH, New York, 2001.
2. For reviews of enantioselective radical reactions, see: a) M. P. Sibi, N. A. Porter, Acc. Chem. Res. 1999, 32, 163-171;
3. b) M. P. Sibi, T. R. Rheault in Radicals in Organic Synthesis (Eds.: M. P. Sibi, P. Renaud), Wiley-VCH, New York, 2001, pp. 461-478.
4. For recent developments in enantioselective radical reactions, see: a) M. P. Sibi, Y. Asano, J. B. Sausker, Angew. Chem. 2001, 113, 1333-1336; Angew. Chem. Int. Ed. 2001, 40, 1293-1296;
5. For recent developments in enantioselective radical reactions, see: a) M. P. Sibi, Y. Asano, J. B. Sausker, Angew. Chem. 2001, 113, 1333-1336; Angew. Chem. Int. Ed. 2001, 40, 1293-1296;
6. b) Y. Watanabe, N. Mase, R. Furue, T. Toru, Tetrahedron Lett. 2001, 42, 2981-2984;
7. c) M. Murakata, H. Tsutsui, O. Hoshino, Org. Lett. 2001, 3, 299-302;
8. d) M. Kurihara, T. Hayashi, N. Miyata, Chem. Lett. 2001, 1324-1325;
9. e) D. Yang, S. Gu, Y.-L. Yan, N.-Y. Zhu, K.-K. Cheung, J. Am. Chem. Soc. 2001, 123, 8612-8613;
10. f) M. P. Sibi, J. Chen, J. Am. Chem. Soc. 2001, 123, 9472-9473;
11. g) M. P. Sibi, J. B. Sausker, J. Am. Chem. Soc. 2002, 124, 984-991;
12. h) Y. D. Cai, B. P. Roberts, D. A. Tocher, J. Chem. Soc. Perkin Trans. 1 2002, 1376-1386;
13. i) M. P. Sibi, S. Manyem, Org. Lett. 2002, 4, 2929-2932;
14. j) D. Yang, S. Gu, Y.-L. Yan, H.-W. Zhao, N.-Y. Zhu, Angew. Chem. 2002, 114, 3140-3143; Angew. Chem. Int. Ed. 2002, 41, 3014-3017;
15. j) D. Yang, S. Gu, Y.-L. Yan, H.-W. Zhao, N.-Y. Zhu, Angew. Chem. 2002, 114, 3140-3143; Angew. Chem. Int. Ed. 2002, 41, 3014-3017;
16. k) A. Gansäuer, H. Bluhm, B. Rinker, S. Narayan, M. Schick, T. Lauterbach, M. Pierobon, Chem. Eur. J. 2003, 9, 531-542.
17. For reviews of radical additions to C=N bonds, see: G. K. Friestad, Tetrahedron 2001, 57, 5461-5496; A. G. Fallis, I. M. Brinza, Tetrahedron 1997, 53, 17 543-17 594.
18. For reviews of radical additions to C=N bonds, see: G. K. Friestad, Tetrahedron 2001, 57, 5461-5496; A. G. Fallis, I. M. Brinza, Tetrahedron 1997, 53, 17 543-17 594.
19. H. Miyabe, K. Fujii, T. Naito, Org. Lett. 1999, 1 569-572.
20. a) H. Miyabe, C. Ushiro, T. Naito, Chem. Commun. 1997, 1789-1790;
21. b) H. Miyabe, C. Ushiro, M. Ueda, K. Yamakawa, T. Naito, J. Org. Chem. 2000, 65, 176-185;
22. c) H. Miyabe, N. Yoshioka, M. Ueda, T. Naito, J. Chem. Soc. Perkin Trans. 1 1998, 3659-3660.
23. M. P. Bertrand, L. Feray, R. Nouguier, L. Stella, Synlett 1998, 780-782; M. P. Bertrand, L. Feray, R. Nouguier, P. Perfetti, Synlett 1999, 1148-1150; M. P. Bertrand, S. Coantic, L. Feray, R. Nouguier, P. Perfetti, Tetrahedron 2000, 56, 3951-3961.
24. M. P. Bertrand, L. Feray, R. Nouguier, L. Stella, Synlett 1998, 780-782; M. P. Bertrand, L. Feray, R. Nouguier, P. Perfetti, Synlett 1999, 1148-1150; M. P. Bertrand, S. Coantic, L. Feray, R. Nouguier, P. Perfetti, Tetrahedron 2000, 56, 3951-3961.
25. M. P. Bertrand, L. Feray, R. Nouguier, L. Stella, Synlett 1998, 780-782; M. P. Bertrand, L. Feray, R. Nouguier, P. Perfetti, Synlett 1999, 1148-1150; M. P. Bertrand, S. Coantic, L. Feray, R. Nouguier, P. Perfetti, Tetrahedron 2000, 56, 3951-3961.
26. G. K. Friestad, J. Qin, J. Am. Chem. Soc. 2000, 122, 8329-8330; G. K. Friestad, J. Qin, J. Am. Chem. Soc. 2001, 123, 9922-9923.
27. G. K. Friestad, J. Qin, J. Am. Chem. Soc. 2000, 122, 8329-8330; G. K. Friestad, J. Qin, J. Am. Chem. Soc. 2001, 123, 9922-9923.
28. N. Halland, K. A. Jørgensen, J. Chem. Soc. Perkin Trans. 1 2001, 1290-1295.
29. Enantioselectivities in the two precedents were 52 % ee (1 equiv Lewis acid, 97 % yield)[6b] and 30 % ee (20 mol % Lewis acid, 5 % yield).[9]
30. For discussions of the effects of Lewis acids in radical reactions, see: P. Renaud, M. Gerster, Angew. Chem. 1998, 110, 2704-2722; Angew. Chem. Int. Ed. 1998, 37, 2562-2579; B. Guerin, W. W. Ogilvie, Y. Guindon in Radicals in Organic Synthesis (Eds.: M. P. Sibi, P. Renaud), Wiley-VCH, New York, 2001, pp. 441-460.
31. For discussions of the effects of Lewis acids in radical reactions, see: P. Renaud, M. Gerster, Angew. Chem. 1998, 110, 2704-2722; Angew. Chem. Int. Ed. 1998, 37, 2562-2579; B. Guerin, W. W. Ogilvie, Y. Guindon in Radicals in Organic Synthesis (Eds.: M. P. Sibi, P. Renaud), Wiley-VCH, New York, 2001, pp. 441-460.
32. For discussions of the effects of Lewis acids in radical reactions, see: P. Renaud, M. Gerster, Angew. Chem. 1998, 110, 2704-2722; Angew. Chem. Int. Ed. 1998, 37, 2562-2579; B. Guerin, W. W. Ogilvie, Y. Guindon in Radicals in Organic Synthesis (Eds.: M. P. Sibi, P. Renaud), Wiley-VCH, New York, 2001, pp. 441-460.
33. Hydrazones 2 were prepared from 1-amino-2-piperidinone and aldehydes by established procedures: P. A. S. Smith, H. G. Pars, J. Org. Chem. 1959, 24, 1325-1332; M. Hajimu, M. Takezawa, H. Shibai, T. Okawara, M. Furukawa, Agric. Biol. Chem. 1986, 50, 1757-1764.
34. Hydrazones 2 were prepared from 1-amino-2-piperidinone and aldehydes by established procedures: P. A. S. Smith, H. G. Pars, J. Org. Chem. 1959, 24, 1325-1332; M. Hajimu, M. Takezawa, H. Shibai, T. Okawara, M. Furukawa, Agric. Biol. Chem. 1986, 50, 1757-1764.
35. The analogous pyrrolidinone-derived hydrazone was inferior, suggesting that the differences in reactivity between 1 and 2 were not solely attributable to electronic effects. For examples of the effects of achiral templates on enantioselective reactions, see references [3c] and [3g].
36. 3B could promote addition to 2 a.
37. Reversal of selectivity suggests a change in the coordination geometry of the Lewis acid upon changing the solvent. For a related discussion, see: M. P. Sibi, M. Liu, Curr. Org. Chem. 2001, 5, 719-755.
38. The R configuration of (+)-8 a (see Supporting Information for proof), is consistent with a distorted square-planar Lewis acid coordination geometry[17] and addition to the more sterically exposed hydrazone Re face, although further mechanistic study is required.
39. D. A. Evans, J. S. Johnson, E. J. Olhava, J. Am. Chem. Soc. 2000, 122, 1635-1649. D. A. Evans, G. S. Peterson, J. S. Johnson, D. M. Barnes, K. R. Campos, K. A. Woerpel, J. Org. Chem. 1998, 63, 4541-4544.
40. D. A. Evans, J. S. Johnson, E. J. Olhava, J. Am. Chem. Soc. 2000, 122, 1635-1649. D. A. Evans, G. S. Peterson, J. S. Johnson, D. M. Barnes, K. R. Campos, K. A. Woerpel, J. Org. Chem. 1998, 63, 4541-4544.
41. Because ligands 4-7 are pseudoenantiomeric to 3. compound 8 a obtained from these ligands has the opposite configuration.
42. 3B) were detected in some cases, and were separable by flash chromatography.
43. 2 moiety, which may suppress binding of product to catalyst. For related mechanistic proposals, see references [7] and [6c].