First radical addition onto ketenimines: A novel synthesis of indoles

Tetrahedron Letters

Volumn 44, Issue 15, 2003, Pages 3027-3030

  Alajarin, Mateo ^a   Vidal, Angel ^a   Ortin, Maria Mar ^a  

^a UNIVERSITY OF MURCIA   (Spain)

Author keywords

Cyclization; Indoles; Ketenimines; Radical reactions

Indexed keywords

CARBON; IMINE; INDOLE DERIVATIVE; KETENIMINE; RADICAL; UNCLASSIFIED DRUG;

ADDITION REACTION; ARTICLE; ATOMIC PARTICLE; CHEMICAL ANALYSIS; CYCLIZATION; METHODOLOGY; MOLECULAR MECHANICS; SYNTHESIS;

EID: 0037424770     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(03)00562-8     Document Type: Article

References (51)

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21. To our knowledge no examples of radical reactions involving carbodiimides or isocyanates have been reported. For examples of radical addition to isothiocyanates, see: (a) Barton, D. H. R.; Jaszberenyi, J. Cs.; Theodorakis, E. A. Tetrahedron 1992, 48, 2613-2626; (b) Bachi, M. D.; Denenmark, D. J. Org. Chem. 1990, 55, 3442-3444; (c) Bachi, M. D.; Bar-Ner, N.; Melman, A. J. Org. Chem. 1996, 61, 7116-7124; (d) Benati, L.; Leardini, R.; Minozzi, M.; Nanni, D.; Spagnolo, P.; Zanardi, G. J. Org. Chem. 2000, 65, 8669-8674.
22. To our knowledge no examples of radical reactions involving carbodiimides or isocyanates have been reported. For examples of radical addition to isothiocyanates, see: (a) Barton, D. H. R.; Jaszberenyi, J. Cs.; Theodorakis, E. A. Tetrahedron 1992, 48, 2613-2626; (b) Bachi, M. D.; Denenmark, D. J. Org. Chem. 1990, 55, 3442-3444; (c) Bachi, M. D.; Bar-Ner, N.; Melman, A. J. Org. Chem. 1996, 61, 7116-7124; (d) Benati, L.; Leardini, R.; Minozzi, M.; Nanni, D.; Spagnolo, P.; Zanardi, G. J. Org. Chem. 2000, 65, 8669-8674.
23. To our knowledge no examples of radical reactions involving carbodiimides or isocyanates have been reported. For examples of radical addition to isothiocyanates, see: (a) Barton, D. H. R.; Jaszberenyi, J. Cs.; Theodorakis, E. A. Tetrahedron 1992, 48, 2613-2626; (b) Bachi, M. D.; Denenmark, D. J. Org. Chem. 1990, 55, 3442-3444; (c) Bachi, M. D.; Bar-Ner, N.; Melman, A. J. Org. Chem. 1996, 61, 7116-7124; (d) Benati, L.; Leardini, R.; Minozzi, M.; Nanni, D.; Spagnolo, P.; Zanardi, G. J. Org. Chem. 2000, 65, 8669-8674.
24. To our knowledge no examples of radical reactions involving carbodiimides or isocyanates have been reported. For examples of radical addition to isothiocyanates, see: (a) Barton, D. H. R.; Jaszberenyi, J. Cs.; Theodorakis, E. A. Tetrahedron 1992, 48, 2613-2626; (b) Bachi, M. D.; Denenmark, D. J. Org. Chem. 1990, 55, 3442-3444; (c) Bachi, M. D.; Bar-Ner, N.; Melman, A. J. Org. Chem. 1996, 61, 7116-7124; (d) Benati, L.; Leardini, R.; Minozzi, M.; Nanni, D.; Spagnolo, P.; Zanardi, G. J. Org. Chem. 2000, 65, 8669-8674.
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29. Allen A.D., Fenwick M.H., Henry-Riyad H., Tidwell T.T. J. Org. Chem. 66:2001;5759-5765.
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31. Tidwell T.T., Fenwick M.H. Eur. J. Org. Chem. 2001;3415-3419.
32. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
33. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
34. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
35. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
36. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
37. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
38. For radical cyclizations leading to indoles, see: (a) Gribble, G. W. Contemp. Org. Synth. 1994, 1, 145-172; (b) Gribble, G. W. J. Chem. Soc., Perkin Trans. 1 2000, 1045-1075; (c) Tokuyama, H.; Yamashita, T.; Reding, M. T.; Kaburagi, Y.; Fukuyama, T. J. Am. Chem. Soc. 1999, 121, 3791-3792; (d) Reding, M. T.; Kaburagi, Y.; Tokuyama, H.; Fukuyama, T. Heterocycles 2002, 56, 313-330; (e) Murphy, J. A.; Scott, K. A.; Sinclair, R. S.; Lewis, N. Tetrahedron Lett. 1997, 38, 7295-7298; (f) Montevecchi, P. C.; Navacchia, M. L. Tetrahedron Lett. 1998, 39, 9077-9080; (g) Rainier, J. D.; Kennedy, A. R.; Chase, E. Tetrahedron Lett. 1999, 40, 6325-6327.
39. For reviews on the radical xanthate transfer reaction, see: (a) Zard, S. Z. reference 1g, pp. 90-108; (b) Zard, S. Z. Angew. Chem., Int. Ed. Engl. 1997, 36, 672-685; (c) Quiclet-Sire, B.; Zard, S. Z. Phosphorus, Sulfur Silicon 1999, 153-154, 137-154.
40. For reviews on the radical xanthate transfer reaction, see: (a) Zard, S. Z. reference 1g, pp. 90-108; (b) Zard, S. Z. Angew. Chem., Int. Ed. Engl. 1997, 36, 672-685; (c) Quiclet-Sire, B.; Zard, S. Z. Phosphorus, Sulfur Silicon 1999, 153-154, 137-154.
41. For reviews on the radical xanthate transfer reaction, see: (a) Zard, S. Z. reference 1g, pp. 90-108; (b) Zard, S. Z. Angew. Chem., Int. Ed. Engl. 1997, 36, 672-685; (c) Quiclet-Sire, B.; Zard, S. Z. Phosphorus, Sulfur Silicon 1999, 153-154, 137-154.
42. 2-Azidobenzylbromides and chlorides 1 have been prepared following general experimental procedures previously described: (a) Molina, P.; Alajarin, M.; Vidal, A. J. Org. Chem. 1993, 58, 1687-1695; (b) Alajarin, M.; Lopez-Lazaro, A.; Vidal, A.; Berna, J. Chem. Eur. J. 1998, 4, 2558-2570.
43. 2-Azidobenzylbromides and chlorides 1 have been prepared following general experimental procedures previously described: (a) Molina, P.; Alajarin, M.; Vidal, A. J. Org. Chem. 1993, 58, 1687-1695; (b) Alajarin, M.; Lopez-Lazaro, A.; Vidal, A.; Berna, J. Chem. Eur. J. 1998, 4, 2558-2570.
44. A small amount (17%) of the imidate resulting from the addition of methanol to the central carbon atom of the cumulene function in ketenimine 4c was also isolated in this reaction.
45. 16ClN: C, 79.36; H, 5.07; N, 4.41. Found: C, 79.12; H, 4.98; N, 4.23.
46. This is the reason why the formation of 5/6 requires stoichiometric quantities of peroxide.
47. Coppa F., Fontana F., Minisci F., Pianese G., Tortoreto P., Zhao L. Tetrahedron Lett. 33:1992;687-690.
48. Gagosz F., Moutrille C., Zard S.Z. Org. Lett. 4:2002;2707-2709.
49. For radical xanthate reaction transfers in which small amounts of reduced side products are obtained, see: (a) Kaoudi, T.; Quiclet-Sire, B.; Seguin, S.; Zard, S. Z. Angew. Chem., Int. Ed. Engl. 2000, 39, 731-733; (b) Kaoudi, T.; Miranda, L. D.; Zard, S. Z. Org. Lett. 2001, 3, 3125-3127. For similar reactions in which cyclohexane acts as an effective hydrogen atom donor, see: (c) Quiclet-Sire, B.; Zard, S. Z. J. Am. Chem. Soc. 1996, 118, 9190-9191.
50. For radical xanthate reaction transfers in which small amounts of reduced side products are obtained, see: (a) Kaoudi, T.; Quiclet-Sire, B.; Seguin, S.; Zard, S. Z. Angew. Chem., Int. Ed. Engl. 2000, 39, 731-733; (b) Kaoudi, T.; Miranda, L. D.; Zard, S. Z. Org. Lett. 2001, 3, 3125-3127. For similar reactions in which cyclohexane acts as an effective hydrogen atom donor, see: (c) Quiclet-Sire, B.; Zard, S. Z. J. Am. Chem. Soc. 1996, 118, 9190-9191.
51. For radical xanthate reaction transfers in which small amounts of reduced side products are obtained, see: (a) Kaoudi, T.; Quiclet-Sire, B.; Seguin, S.; Zard, S. Z. Angew. Chem., Int. Ed. Engl. 2000, 39, 731-733; (b) Kaoudi, T.; Miranda, L. D.; Zard, S. Z. Org. Lett. 2001, 3, 3125-3127. For similar reactions in which cyclohexane acts as an effective hydrogen atom donor, see: (c) Quiclet-Sire, B.; Zard, S. Z. J. Am. Chem. Soc. 1996, 118, 9190-9191.