On the Viability of Oxametallacyclic Intermediates in the (salen)Mn-Catalyzed Asymmetric Epoxidation

Angewandte Chemie (International Edition in English)

Volumn 36, Issue 16, 1997, Pages 1720-1723

  Finney, Nathaniel S ^a   Pospisil, Paul J ^a   Chang, Sukbok ^a   Palucki, Michael ^a   Konsler, Reed G ^a   Hansen, Karl B ^a   Jacobsen, Eric N ^a  

^a HARVARD UNIVERSITY   (United States)

Author keywords

Epoxidations; Manganese; Oxidations; Radicals

Indexed keywords

EID: 0030876233     PISSN: 05700833     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.199717201     Document Type: Article

References (52)

1. a) Cytochrome P-450. Structure, Mechanism, and Biochemistry, 2nd ed. (Ed.: P. R. Ortiz de Montellano), Plenum, New York, 1996;
2. b) M. K. Stern, J. T. Groves, Manganese Redox Enzymes (Ed.: V. L. Pecoraro), VCH, New York, 1992, chap. 11;
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4. d) R. H. Holm, Chem. Rev. 1987, 87, 1401;
5. e) E. N. Jacobsen, Comprehensive Organometallic Chemistry II, Vol. 12 (Eds.: G. Wilkinson. F. G. A. Stone, E. W. Abel, L. S. Hegedus), Pergamon, New York, 1995, chap. 11.1.
6. a) K. A. Jørgensen, B. Schiøtt, Chem. Rev. 1990, 90, 1483;
7. b) P.-O. Norrby, H. Becker, K. B. Sharpless, J. Am. Chem. Soc. 1996, 118, 35, and references therein.
8. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
9. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
10. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
11. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
12. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
13. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
14. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
15. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
16. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
17. Porphyrin-based catalysts: a) J. T. Groves, T. E. Nemo, R. S. Myers, J. Am. Chem. Soc. 1979, 101, 1032; b) J. T. Groves, R. S. Myers, ibid. 1983, 105, 5791; c) K. A. Jørgensen, Chem. Rev. 1989, 89, 431; d) D. Ostovic, T. C. Bruice, Acc. Chem. Res. 1992, 25, 312; e) J. P. Collman, X. Zhang, V. J. Lee, E. S. Uffelman, J. I. Brauman, Science 1993, 261, 1404; salen-based catalysts: f) E. G. Samsel, K. Srinivasan, J. K. Kochi, J. Am. Chem. Soc. 1985, 107, 7606; g) K. Srinivasan, P. Michaud, J. K. Kochi, ibid. 1986, 108, 2309; h) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, ibid. 1990, 112, 2801; i) E. N. Jacobsen, L. Deng, Y. Furukawa, L. E. Martínez, Tetrahedron 1993, 50, 4323; j) N. Hosoya, A. Hatayama, K. Yanai, H. Fujii, R. Irie, T. Katsuki, Synlett 1993, 641.
18. P.-O. Norrby, C. Linde, B. Åkermark, J. Am. Chem. Soc. 1995, 117, 11035.
19. a) T. Hamada, T. Fukuda, H. Imanishi, T. Katsuki, Tetrahedron 1996, 52, 515;
20. b) T. Katsuki, J. Synth. Org. Chem. Jpn. 1996, 53, 940.
21. T. Katsuki, Coord. Chem. Rev. 1995, 140, 189.
22. For previous studies of the effect of additives in (salen)M catayst sytems, see ref. [3f,g,i] and a) R. Irie, K. Noda, Y. Ito, N. Matsumoto, T. Katsuki, Tetrahedron: Asymmetry 1991, 2, 481; b) M. Paiucki, P. J. Pospisil, W. Zhang, E. N. Jacobsen, J. Am. Chem. Soc. 1994, 116, 9333; c) C. H. Senanayake, G. B. Smith, J. Liu, L. E. Fredenburgh, K. M. Ryan, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, Tetrahedron Lett. 1995, 36, 3993; d) C. H. Senanayake, G. B. Smith, K. M. Ryan, L. E. Fredenburgh, J. Liu, F. Roberts, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, ibid. 1996, 37, 3271.
23. For previous studies of the effect of additives in (salen)M catayst sytems, see ref. [3f,g,i] and a) R. Irie, K. Noda, Y. Ito, N. Matsumoto, T. Katsuki, Tetrahedron: Asymmetry 1991, 2, 481; b) M. Paiucki, P. J. Pospisil, W. Zhang, E. N. Jacobsen, J. Am. Chem. Soc. 1994, 116, 9333; c) C. H. Senanayake, G. B. Smith, J. Liu, L. E. Fredenburgh, K. M. Ryan, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, Tetrahedron Lett. 1995, 36, 3993; d) C. H. Senanayake, G. B. Smith, K. M. Ryan, L. E. Fredenburgh, J. Liu, F. Roberts, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, ibid. 1996, 37, 3271.
24. For previous studies of the effect of additives in (salen)M catayst sytems, see ref. [3f,g,i] and a) R. Irie, K. Noda, Y. Ito, N. Matsumoto, T. Katsuki, Tetrahedron: Asymmetry 1991, 2, 481; b) M. Paiucki, P. J. Pospisil, W. Zhang, E. N. Jacobsen, J. Am. Chem. Soc. 1994, 116, 9333; c) C. H. Senanayake, G. B. Smith, J. Liu, L. E. Fredenburgh, K. M. Ryan, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, Tetrahedron Lett. 1995, 36, 3993; d) C. H. Senanayake, G. B. Smith, K. M. Ryan, L. E. Fredenburgh, J. Liu, F. Roberts, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, ibid. 1996, 37, 3271.
25. For previous studies of the effect of additives in (salen)M catayst sytems, see ref. [3f,g,i] and a) R. Irie, K. Noda, Y. Ito, N. Matsumoto, T. Katsuki, Tetrahedron: Asymmetry 1991, 2, 481; b) M. Paiucki, P. J. Pospisil, W. Zhang, E. N. Jacobsen, J. Am. Chem. Soc. 1994, 116, 9333; c) C. H. Senanayake, G. B. Smith, J. Liu, L. E. Fredenburgh, K. M. Ryan, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, Tetrahedron Lett. 1995, 36, 3993; d) C. H. Senanayake, G. B. Smith, K. M. Ryan, L. E. Fredenburgh, J. Liu, F. Roberts, D. L. Hughes, R. D. Larsen, T. R. Verhoeven, P. J. Reider, ibid. 1996, 37, 3271.
26. A. Suárez, P. J. Pospisil, E. N. Jacobsen, unpublished results; see also ref. [7c,d].
27. The X-ray crystal structure of a cationic O=Cr(salen) complex with an axially coordinated N-oxide has been reported [3f].
28. Enantioselectivities and cis/trans ratios in epoxidations with 1 are also unaffected by added 4-PPNO.
29. A full account of the synthesis and structural analysis of catalyst 1 will be published elsewhere: S. B. Chang, K. B. Hansen, E. N. Jacobsen, unpublished results.
30. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
31. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
32. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
33. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
34. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
35. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
36. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
37. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
38. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
39. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
40. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
41. III complexes contain near-planar salen moieties and axially coordinated spectator ligands and/or counterions: a) W. Zhang, J. L. Loebach, S. R. Wilson, E. N. Jacobsen, J. Am. Chem. Soc. 1990, 112, 2801; b) P. J. Pospisil, D. H. Carsten, E. N. Jacobsen, Chem. Eur. J. 1996, 2, 974; c) M. T. Rispens, A. Meetsma, B. L. Feringa, Recl. Trav. Chim. Pays-Bas 1994, 113, 413. For examples of structurally characterized achiral (salen)Mn complexes, see ref. [3g] and d) J. E. Davies, B. M. Gatehouse, J. Chem. Soc. Dalton Trans. 1973, 2523; e) V. L. Pecoraro, W. M. Butler, Acta Crystallogr. Sect. C 1986, 42, 1151; f) J. W. Gohdes, W. H. Armstrong, Inorg. Chem. 1988, 27, 1841; g) X. Li, V. L. Pecoraro, Inorg. Chem. 1989, 28, 3403; h) N. Matsumoto, H. Okawa, S. Kida, T. Ogawa, A. Ohyoshi, Bull. Chem. Soc. Jpn. 1989, 62, 3812; i) M. Mikuriya, Y. Yamato, T. Tokii, ibid. 1992, 65, 1466; j) A. Garcia-Deibe, A. Sousa, M. R. Bermejo, P. P. MacRory, C. A. McAuliffe, R. G. Pritchard, M. Helliwell, J. Chem. Soc. Chem. Commun. 1991, 728; k) A. R. Oki, D. J. Hodgson, Inorg. Chim. Acta 1990, 170, 65; l) W. Chiang, D. M. Ho, D. Van Engen, M. E. Thompson, Inorg. Chem. 1993, 32, 2886.
42. One of the principal difficulties encountered in evaluating the radical mechanism is the question of how an essentially flat ligand system can impart such exquisite levels of enantioselectivity with a wide range of substrates. This has served as the impetus for the proposal by Norrby et al. [4] of the 6-coordinate oxametallacyclic intermediate B. Credence was lent to this pathway by calculations based on empirical force-field models, which predicted significant differences in energy between diastereomeric 6-coordinate (salen)Mn oxametalla-cycles. The documented effect of amine N-oxide derivatives on the epoxidation rules put such intermediates. Still, it is worth considering whether a similar computational analysis of the radical mechanism stands up well against available enantioselectivity data. We performed semi-empirical calculations of the diastereomeric radical intermediates for the epoxidation of phenylcyclohexene (PM3 (tm) parameters, Spartan version 4.0). This analysis indicates that the enantioselectivity of the epoxidation reaction may be readily ascribed to energetic differences between diastereomeric radical intermediates, and that the radical mechanism is perfectly consistent with enantioselective epoxide formation.
43. For example, epoxidation of triphenylethylene catalyzed by 3 provides triphenylethylene oxide in 92% ee and 97% yield, and epoxidation of phenylcyclohexene proceeds in 88% ee and 67% yield: B. D. Brandes, E. N. Jacobsen, J. Org. Chem. 1994, 59, 4378. Similarly, epoxidation of 3′-bromo-2,2,3,4-tetramethylchromene employing 5 provides the corresponding chromene oxide in 96% ee and 84% yield: B. D. Brandes, E. N. Jacobsen, Tetrahedron Lett. 1995, 36, 5123.
44. For example, epoxidation of triphenylethylene catalyzed by 3 provides triphenylethylene oxide in 92% ee and 97% yield, and epoxidation of phenylcyclohexene proceeds in 88% ee and 67% yield: B. D. Brandes, E. N. Jacobsen, J. Org. Chem. 1994, 59, 4378. Similarly, epoxidation of 3′-bromo-2,2,3,4-tetramethylchromene employing 5 provides the corresponding chromene oxide in 96% ee and 84% yield: B. D. Brandes, E. N. Jacobsen, Tetrahedron Lett. 1995, 36, 5123.
45. Similar steric arguments were made to exlude the formation of oxametalla-cycles in oxidations catalyzed by metal porphyrin complexes [3d].
46. Iodosylbenzene, the terminal oxidant employed by Katsuki et al., is only sparingly soluble in organic solvents.
47. J. F. Larrow, E. N. Jacobsen, J. Am. Chem. Soc. 1994, 116, 12129.
48. The (salen)Mn-catalyzed oxidation of aryl sulfides proceeds with the same absolute sense of enantioinduction as for styrene derivatives: a) M. Palucki, P. Hanson, E. N. Jacobsen, Tetrahedron Lett. 1992, 33, 7111; b) K. Noda, N. Hosoya, Y. Yamashita, T. Katsuki, Tetrahedron 1994, 50, 9609. Sulfide oxidation clearly cannot proceed via oxametallacyclic or related intermediates.
49. The (salen)Mn-catalyzed oxidation of aryl sulfides proceeds with the same absolute sense of enantioinduction as for styrene derivatives: a) M. Palucki, P. Hanson, E. N. Jacobsen, Tetrahedron Lett. 1992, 33, 7111; b) K. Noda, N. Hosoya, Y. Yamashita, T. Katsuki, Tetrahedron 1994, 50, 9609. Sulfide oxidation clearly cannot proceed via oxametallacyclic or related intermediates.
50. P. Boehner in Ockham: Philosophical Writings, Nelson, New York, 1957, p. xxi. Fora recent discussion of the role of intellectual parsimony in scientific endeavor, see R. Hoffmann, V. I. Minkin, B. K. Carpenter, Bull. Soc. Chim. Fr. 1996, 133, 117.
51. P. Boehner in Ockham: Philosophical Writings, Nelson, New York, 1957, p. xxi. Fora recent discussion of the role of intellectual parsimony in scientific endeavor, see R. Hoffmann, V. I. Minkin, B. K. Carpenter, Bull. Soc. Chim. Fr. 1996, 133, 117.
52. W. Zhang, E. N. Jacobsen, J. Org. Chem. 1991, 56, 2296.