Fluorinated chiral secondary amines as catalysts for epoxidation of olefins with oxone

Journal of Organic Chemistry

Volumn 70, Issue 3, 2005, Pages 898-906

  Ho, Chun Yu ^a   Chen, Ying Chun ^a   Wong, Man Kin ^a   Yang, Dan ^a  

^a UNIVERSITY OF HONG KONG   (Hong Kong)

Author keywords

[No Author keywords available]

Indexed keywords

AMMONIUM COMPOUNDS; CATALYSTS; FLUORINE; OLEFINS; REACTION KINETICS; SCREENING; SYNTHESIS (CHEMICAL);

1-PHENYLCYCLOHEXENE; EPOXIDATION REACTIONS; OXONE; PHASE TRANSFER;

AMINES;

ALKENE; AMINE; AMMONIUM DERIVATIVE; FLUORINE; SODIUM CHLORIDE; SODIUM PEROXIDE;

ACIDIFICATION; ARTICLE; CATALYST; CHIRALITY; EPOXIDATION; FLUORINATION; PHASE TRANSITION; SUBSTITUTION REACTION;

EID: 13244292377     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo048378t     Document Type: Article

References (68)

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18. For asymmetric epoxidations with chiral dioxiranes, see: (a) Yang, D.; Jiao, G. S.; Yip, Y. C.; Lai, T. H.; Wong, M. K. J. Org. Chem. 2001, 66, 4619-4624. (b) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (c) Yang, D.; Wong, M. K.; Yip, Y. C.; Wang, X. C.; Tang, M. W.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 5943-5952. (d) Yang, D.; Wang, X. C.; Wong, M. K.; Yip, Y. C.; Tang, M. W. J. Am. Chem. Soc. 1998, 118, 11311-11312. (e) Yang, D.; Yip, Y. C.; Tang, M. W.; Wong, M. K.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1996, 118, 491-492.
19. For asymmetric epoxidations with chiral dioxiranes, see: (a) Yang, D.; Jiao, G. S.; Yip, Y. C.; Lai, T. H.; Wong, M. K. J. Org. Chem. 2001, 66, 4619-4624. (b) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (c) Yang, D.; Wong, M. K.; Yip, Y. C.; Wang, X. C.; Tang, M. W.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 5943-5952. (d) Yang, D.; Wang, X. C.; Wong, M. K.; Yip, Y. C.; Tang, M. W. J. Am. Chem. Soc. 1998, 118, 11311-11312. (e) Yang, D.; Yip, Y. C.; Tang, M. W.; Wong, M. K.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1996, 118, 491-492.
20. For asymmetric epoxidations with chiral dioxiranes, see: (a) Yang, D.; Jiao, G. S.; Yip, Y. C.; Lai, T. H.; Wong, M. K. J. Org. Chem. 2001, 66, 4619-4624. (b) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (c) Yang, D.; Wong, M. K.; Yip, Y. C.; Wang, X. C.; Tang, M. W.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 5943-5952. (d) Yang, D.; Wang, X. C.; Wong, M. K.; Yip, Y. C.; Tang, M. W. J. Am. Chem. Soc. 1998, 118, 11311-11312. (e) Yang, D.; Yip, Y. C.; Tang, M. W.; Wong, M. K.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1996, 118, 491-492.
21. For asymmetric epoxidations with chiral dioxiranes, see: (a) Yang, D.; Jiao, G. S.; Yip, Y. C.; Lai, T. H.; Wong, M. K. J. Org. Chem. 2001, 66, 4619-4624. (b) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (c) Yang, D.; Wong, M. K.; Yip, Y. C.; Wang, X. C.; Tang, M. W.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 5943-5952. (d) Yang, D.; Wang, X. C.; Wong, M. K.; Yip, Y. C.; Tang, M. W. J. Am. Chem. Soc. 1998, 118, 11311-11312. (e) Yang, D.; Yip, Y. C.; Tang, M. W.; Wong, M. K.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1996, 118, 491-492.
22. For asymmetric epoxidations with chiral dioxiranes, see: (a) Yang, D.; Jiao, G. S.; Yip, Y. C.; Lai, T. H.; Wong, M. K. J. Org. Chem. 2001, 66, 4619-4624. (b) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (c) Yang, D.; Wong, M. K.; Yip, Y. C.; Wang, X. C.; Tang, M. W.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 5943-5952. (d) Yang, D.; Wang, X. C.; Wong, M. K.; Yip, Y. C.; Tang, M. W. J. Am. Chem. Soc. 1998, 118, 11311-11312. (e) Yang, D.; Yip, Y. C.; Tang, M. W.; Wong, M. K.; Zheng, J. H.; Cheung, K. K. J. Am. Chem. Soc. 1996, 118, 491-492.
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25. For amine-catalyzed epoxidations, see: (a) Adamo, M. F. A.; Aggarwal, V. K.; Sage, M. A. J. Am. Chem. Soc. 2000, 122, 8317-8318. (b) Adamo, M. F. A.; Aggarwal, V. K.; Sage, M. A J. Am. Chem. Soc. 2002, 124, 11223. (c) Aggarwal, V. K.; Lopin, C.; Sandrinelli, P. J. Am. Chem. Soc. 2003, 125, 7596-7601.
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28. The reasons why β-hydroxylamines efficiently promote epoxidation of olefins are under investigation.
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30. In the amine-catalyzed epoxidation of trans-stilbene with amine 8c, the amine subsequently decomposed to give benzophenone and nitrone. (a) Su, Z.; Mariano, P. K.; Falvey, D. E.; Yoon, U. C.; Oh, S. W. J. Am. Chem. Soc. 1998, 120, 10676-10686. (b) Murahashi, S.-I.; Imada, Y.; Ohtake, H. J. Org. Chem. 1994, 59, 6170-6172.
31. The procedures for the preparation of amines 9a-c, 10, 12b-g, 13a-c, and 14 are provided in the Supporting Information.
32. We found that under our slightly acidic reaction system, cis-1,2-diol is the major hydrolysis product of 1-phenylcyclohexene oxide. This finding is in agreement with literature reports that the cis-1,2-diol is more stable than the trans-1,2-diol. (a) Berti, G.; Bottari, F.; Macchia, B.; Macchia, F. J. Org. Chem. 1952, 17, 6227-6234. (b) Choudary, B. M.; Chowdari, N. S.; Jyothi, K.; Kantam, M. L. Tetrahedron 1965, 12, 3277-3283.
33. We found that under our slightly acidic reaction system, cis-1,2-diol is the major hydrolysis product of 1-phenylcyclohexene oxide. This finding is in agreement with literature reports that the cis-1,2-diol is more stable than the trans-1,2-diol. (a) Berti, G.; Bottari, F.; Macchia, B.; Macchia, F. J. Org. Chem. 1952, 17, 6227-6234. (b) Choudary, B. M.; Chowdari, N. S.; Jyothi, K.; Kantam, M. L. Tetrahedron 1965, 12, 3277-3283.
34. 1H NMR spectroscopy of the enantiomeric purities of chiral carboxylic acids and alcohols. See: (a) O'Hagan, D.; Royer, F.; Tavasli, M. Tetrahedron: Asymmetry 2000, 11, 2033-2036. (b) Bailey, D. J.; O'Hagan, D.; Tavasli, M. Tetrahedron: Asymmetry 1997, 8, 149-153.
35. 1H NMR spectroscopy of the enantiomeric purities of chiral carboxylic acids and alcohols. See: (a) O'Hagan, D.; Royer, F.; Tavasli, M. Tetrahedron: Asymmetry 2000, 11, 2033-2036. (b) Bailey, D. J.; O'Hagan, D.; Tavasli, M. Tetrahedron: Asymmetry 1997, 8, 149-153.
36. For examples of the use of fluorinated compounds as enzyme substrate mimics, see: (a) Welch, J. T.; Eswarakrishnan, S. Fluorine in Bioorganic Chemistry; Wiley & Sons: New York, 1991. (b) Seebach, D. Angew Chem., Int. Ed. Engl. 1990, 29, 1320-1367. (c) Mann, J. Chem. Soc. Rev. 1987, 16, 381-436. (d) Welch, J. T. Tetrahedron 1987, 43, 3123-3197. (e) Bondi, A. J. Phys. Chem. 1984, 68, 441-451.
37. For examples of the use of fluorinated compounds as enzyme substrate mimics, see: (a) Welch, J. T.; Eswarakrishnan, S. Fluorine in Bioorganic Chemistry; Wiley & Sons: New York, 1991. (b) Seebach, D. Angew Chem., Int. Ed. Engl. 1990, 29, 1320-1367. (c) Mann, J. Chem. Soc. Rev. 1987, 16, 381-436. (d) Welch, J. T. Tetrahedron 1987, 43, 3123-3197. (e) Bondi, A. J. Phys. Chem. 1984, 68, 441-451.
38. For examples of the use of fluorinated compounds as enzyme substrate mimics, see: (a) Welch, J. T.; Eswarakrishnan, S. Fluorine in Bioorganic Chemistry; Wiley & Sons: New York, 1991. (b) Seebach, D. Angew Chem., Int. Ed. Engl. 1990, 29, 1320-1367. (c) Mann, J. Chem. Soc. Rev. 1987, 16, 381-436. (d) Welch, J. T. Tetrahedron 1987, 43, 3123-3197. (e) Bondi, A. J. Phys. Chem. 1984, 68, 441-451.
39. For examples of the use of fluorinated compounds as enzyme substrate mimics, see: (a) Welch, J. T.; Eswarakrishnan, S. Fluorine in Bioorganic Chemistry; Wiley & Sons: New York, 1991. (b) Seebach, D. Angew Chem., Int. Ed. Engl. 1990, 29, 1320-1367. (c) Mann, J. Chem. Soc. Rev. 1987, 16, 381-436. (d) Welch, J. T. Tetrahedron 1987, 43, 3123-3197. (e) Bondi, A. J. Phys. Chem. 1984, 68, 441-451.
40. For examples of the use of fluorinated compounds as enzyme substrate mimics, see: (a) Welch, J. T.; Eswarakrishnan, S. Fluorine in Bioorganic Chemistry; Wiley & Sons: New York, 1991. (b) Seebach, D. Angew Chem., Int. Ed. Engl. 1990, 29, 1320-1367. (c) Mann, J. Chem. Soc. Rev. 1987, 16, 381-436. (d) Welch, J. T. Tetrahedron 1987, 43, 3123-3197. (e) Bondi, A. J. Phys. Chem. 1984, 68, 441-451.
41. For the X-ray crystallographic structure of amine 12a·HCl salts, see: Batsanov, A. S.; Howard, J. A. K. Acta Crystallogr., Sect. C 2000, C56 10, e467-e468.
42. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
43. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
44. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
45. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
46. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
47. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
48. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
49. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
50. For recent examples of electronic effects of catalysts affecting enantioselectivity, see: (a) Cavallo, L.; Jacobsen, H. J. Org. Chem. 2003, 68, 6202-6207. (b) Palucki, M.; Finney, N. S.; Pospisil, P. J.; Gueler, M. L.; Ishida, T.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 948-954. (c) Yang, D.; Yip, Y. C.; Chen, J.; Cheung, K. K. J. Am. Chem. Soc. 1998, 120, 7659-7660. (d) RajanBabu, T. V.; Casalnuovo, A. L. J. Am. Chem. Soc. 1998, 118, 6325-6326. (e) Schnyder, A.; Hintermann, L.; Togni, A. Angew. Chem., Int. Ed. Engl. 1995, 34, 931-933. (f) Park, S. B.; Murata, K.; Matsumoto, H.; Nishiyama, H. Tetrahedron: Asymmetry 1993, 10, 2487-2494. (g) Larrow, J. F.; Jacobsen, E. N.; Gao, Y.; Hong, Y.; Nie, X.; Zepp, C. M. J. Org. Chem. 1994, 59, 1939-1942. (h) Chang, S.; Heid, R. M.; Jacobsen, E. N. Tetrahedron Lett. 1994, 5, 669-672. (i) Jacobsen, E. N.; Zhang, W.; Güler, M. L. J. Am. Chem. Soc. 1991, 113, 6703-6704.
51. For examples of electronic field effects and inductive effects affecting chemical reactivity, see: (a) Yang, D.; Yip, Y. C.; Jiao, G. S.; Wong, M. K. J. Org. Chem. 1998, 63, 8952-8956. (b) Bowden, K.; Grubbs, E. J. Chem. Soc. Rev. 1996, 171-177. (c) Stock, L. M. J. Chem. Educ. 1972, 49, 400-404.
52. For examples of electronic field effects and inductive effects affecting chemical reactivity, see: (a) Yang, D.; Yip, Y. C.; Jiao, G. S.; Wong, M. K. J. Org. Chem. 1998, 63, 8952-8956. (b) Bowden, K.; Grubbs, E. J. Chem. Soc. Rev. 1996, 171-177. (c) Stock, L. M. J. Chem. Educ. 1972, 49, 400-404.
53. For examples of electronic field effects and inductive effects affecting chemical reactivity, see: (a) Yang, D.; Yip, Y. C.; Jiao, G. S.; Wong, M. K. J. Org. Chem. 1998, 63, 8952-8956. (b) Bowden, K.; Grubbs, E. J. Chem. Soc. Rev. 1996, 171-177. (c) Stock, L. M. J. Chem. Educ. 1972, 49, 400-404.
54. For the use of fluorine atoms to improve the hydrophobicity of a catalyst, see: Wu, J. J.; Fu, L.; Chuang, K. T. Appl. Catal. 1991, 72, 71-80.
55. For the determination of the ee values of trans-stilbene oxide and trans-β-methylstyrene oxide, see: (a) Wang, Z. X.; Tu, Y.; Frohn, M.; Shi, Y. J. Org. Chem. 1997, 62, 2328-2329. For trans-α-methyl-stilbene oxide, see: (b) Brandes, B. D.; Jacobsen, E. N. J. Org. Chem. 1994, 59, 4378-4380.
56. For the determination of the ee values of trans-stilbene oxide and trans-β-methylstyrene oxide, see: (a) Wang, Z. X.; Tu, Y.; Frohn, M.; Shi, Y. J. Org. Chem. 1997, 62, 2328-2329. For trans-α-methyl-stilbene oxide, see: (b) Brandes, B. D.; Jacobsen, E. N. J. Org. Chem. 1994, 59, 4378-4380.
57. A nitrone was detected by ESI-MS analysis to be the major oxidation product of amine 12a. For catalytic oxidation of secondary amines to nitrones, see: (a) Murahashi, S. I. Angew. Chem., Int. Ed. Engl. 1995, 34, 2443-2465. (b) Murahashi, S. I.; Mitsui, H.; Shiota, T.; Tsuda, T.; Watanabe, S. J. Org. Chem. 1990, 55, 1736-1744.
58. A nitrone was detected by ESI-MS analysis to be the major oxidation product of amine 12a. For catalytic oxidation of secondary amines to nitrones, see: (a) Murahashi, S. I. Angew. Chem., Int. Ed. Engl. 1995, 34, 2443-2465. (b) Murahashi, S. I.; Mitsui, H.; Shiota, T.; Tsuda, T.; Watanabe, S. J. Org. Chem. 1990, 55, 1736-1744.
59. For substrate syntheses, see: (a) Collins, D. J.; Molinski, T. F.; Sjoevall, J. Aust. J. Chem. 1983, 36, 361-370. (b) Shabarov, Y.; Blagodatskikh, S. A.; Levina, M. I. Zh. Org. Khim. 1975, 11, 1223-1225.
60. For substrate syntheses, see: (a) Collins, D. J.; Molinski, T. F.; Sjoevall, J. Aust. J. Chem. 1983, 36, 361-370. (b) Shabarov, Y.; Blagodatskikh, S. A.; Levina, M. I. Zh. Org. Khim. 1975, 11, 1223-1225.
61. For recent examples of substrate electronic effects affecting enantioselectivity, see: (a) Wang, M.-X.; Lin, S.-J.; Liu, C.-S.; Zheng, Q.-Y.; Li, J.-S. J. Org. Chem. 2003, 68, 4570-4573. (b) Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Bhadbhade, M. M.; Suresh, E. J. Mol. Catal. A: Chem. 1999, 1-2, 185-194. (c) Zhang, H.; Xue, F.; Mak, T. C. W.; Chan, K. S. J. Org. Chem. 1996, 61, 8002-8003. (d) Corey, E. J.; Helal, C. J. Tetrahedron Lett. 1995, 36, 9153-9156.
62. For recent examples of substrate electronic effects affecting enantioselectivity, see: (a) Wang, M.-X.; Lin, S.-J.; Liu, C.-S.; Zheng, Q.-Y.; Li, J.-S. J. Org. Chem. 2003, 68, 4570-4573. (b) Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Bhadbhade, M. M.; Suresh, E. J. Mol. Catal. A: Chem. 1999, 1-2, 185-194. (c) Zhang, H.; Xue, F.; Mak, T. C. W.; Chan, K. S. J. Org. Chem. 1996, 61, 8002-8003. (d) Corey, E. J.; Helal, C. J. Tetrahedron Lett. 1995, 36, 9153-9156.
63. For recent examples of substrate electronic effects affecting enantioselectivity, see: (a) Wang, M.-X.; Lin, S.-J.; Liu, C.-S.; Zheng, Q.-Y.; Li, J.-S. J. Org. Chem. 2003, 68, 4570-4573. (b) Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Bhadbhade, M. M.; Suresh, E. J. Mol. Catal. A: Chem. 1999, 1-2, 185-194. (c) Zhang, H.; Xue, F.; Mak, T. C. W.; Chan, K. S. J. Org. Chem. 1996, 61, 8002-8003. (d) Corey, E. J.; Helal, C. J. Tetrahedron Lett. 1995, 36, 9153-9156.
64. For recent examples of substrate electronic effects affecting enantioselectivity, see: (a) Wang, M.-X.; Lin, S.-J.; Liu, C.-S.; Zheng, Q.-Y.; Li, J.-S. J. Org. Chem. 2003, 68, 4570-4573. (b) Abdi, S. H. R.; Kureshy, R. I.; Khan, N. H.; Bhadbhade, M. M.; Suresh, E. J. Mol. Catal. A: Chem. 1999, 1-2, 185-194. (c) Zhang, H.; Xue, F.; Mak, T. C. W.; Chan, K. S. J. Org. Chem. 1996, 61, 8002-8003. (d) Corey, E. J.; Helal, C. J. Tetrahedron Lett. 1995, 36, 9153-9156.
65. For studies on fluorine atoms as hydrogen bond acceptors using the Cambridge Structural Database System, see: (a) Howard, J. A. K.; Hoy V. J.; O'Hagan, D.; Smith G. T. Tetrahedron 1996, 38, 12613-12622. (b) Shimoni, L.; Glusker, J. P. Struct. Chem. 1994, 5, 383-397. (c) Murray-Rust, P.; Stalling, W. C.; Monti, C. T.; Preston, R. K.; Glusker, J. P. J. Am. Chem. Soc. 1983, 105, 3206-3214.
66. For studies on fluorine atoms as hydrogen bond acceptors using the Cambridge Structural Database System, see: (a) Howard, J. A. K.; Hoy V. J.; O'Hagan, D.; Smith G. T. Tetrahedron 1996, 38, 12613-12622. (b) Shimoni, L.; Glusker, J. P. Struct. Chem. 1994, 5, 383-397. (c) Murray-Rust, P.; Stalling, W. C.; Monti, C. T.; Preston, R. K.; Glusker, J. P. J. Am. Chem. Soc. 1983, 105, 3206-3214.
67. For studies on fluorine atoms as hydrogen bond acceptors using the Cambridge Structural Database System, see: (a) Howard, J. A. K.; Hoy V. J.; O'Hagan, D.; Smith G. T. Tetrahedron 1996, 38, 12613-12622. (b) Shimoni, L.; Glusker, J. P. Struct. Chem. 1994, 5, 383-397. (c) Murray-Rust, P.; Stalling, W. C.; Monti, C. T.; Preston, R. K.; Glusker, J. P. J. Am. Chem. Soc. 1983, 105, 3206-3214.
68. For a heterogeneous solvent system that uses 18-crown-6 and Oxone to perform epoxidation, see: Lacour, J.; Monchaud, D.; Marsol, C. Tetrahedron Lett. 2002, 43, 8257-8260.