Synthesis of Benzofuran Derivatives on Solid Support via SmI2-Mediated Radical Cyclization

Journal of Organic Chemistry

Volumn 62, Issue 17, 1997, Pages 5678-5679

  Du, Xiaohui ^a   Armstrong, Robert W ^a  

^a UNIVERSITY OF CALIFORNIA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

2 PYRROLIDONE DERIVATIVE; BENZOFURAN DERIVATIVE; HEMPA; IODIDE; METHYL CHLORIDE; MORPHOLINE DERIVATIVE; RADICAL; REAGENT; RESIN; SAMARIUM; SOLVENT; TETRAHYDROFURAN DERIVATIVE; TRIFLUOROACETIC ACID;

ARTICLE; CHEMICAL REACTION; CYCLIZATION; DRUG SYNTHESIS; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; SOLID STATE;

EID: 0030826980     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo970913k     Document Type: Article

References (32)

1. For reviews, see: (a) Chem. Rev. 1997, 97, whole issue of No. 2, pp 347-510. (b) Fruchtel, J. S.; Jung, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 17-42. (c) Thompson, L. A.; Ellman, J. A. Chem. Rev. 1996, 96, 555-600. (d) Acc. Chem. Res. 1996, 29, whole issue of No. 3, pp 112-170.
2. For reviews, see: (a) Chem. Rev. 1997, 97, whole issue of No. 2, pp 347-510. (b) Fruchtel, J. S.; Jung, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 17-42. (c) Thompson, L. A.; Ellman, J. A. Chem. Rev. 1996, 96, 555-600. (d) Acc. Chem. Res. 1996, 29, whole issue of No. 3, pp 112-170.
3. For reviews, see: (a) Chem. Rev. 1997, 97, whole issue of No. 2, pp 347-510. (b) Fruchtel, J. S.; Jung, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 17-42. (c) Thompson, L. A.; Ellman, J. A. Chem. Rev. 1996, 96, 555-600. (d) Acc. Chem. Res. 1996, 29, whole issue of No. 3, pp 112-170.
4. For reviews, see: (a) Chem. Rev. 1997, 97, whole issue of No. 2, pp 347-510. (b) Fruchtel, J. S.; Jung, G. Angew. Chem., Int. Ed. Engl. 1996, 35, 17-42. (c) Thompson, L. A.; Ellman, J. A. Chem. Rev. 1996, 96, 555-600. (d) Acc. Chem. Res. 1996, 29, whole issue of No. 3, pp 112-170.
5. For reduction of halide to alkyl, see: Worster, P. M.; McArthur, C. R.; Leznoff, C. C. Angew. Chem., Int. Ed. Engl. 1979, 18, 221-222.
6. For addition of thiol radical to olefin, see (a) Gasparrini, F.; Misiti, D.; Villani, C.; Borchardt, A.; Burger, M. T.; Still, W. C. J. Org. Chem., 1995, 60, 4314-4315. (b) Hodge, P.; Khoshdel, E.; Waterhouse, J.; Frechet, J. M. J. J. Chem. Soc., Perkin Trans, 1 1985, 2327-2331.
7. For addition of thiol radical to olefin, see (a) Gasparrini, F.; Misiti, D.; Villani, C.; Borchardt, A.; Burger, M. T.; Still, W. C. J. Org. Chem., 1995, 60, 4314-4315. (b) Hodge, P.; Khoshdel, E.; Waterhouse, J.; Frechet, J. M. J. J. Chem. Soc., Perkin Trans, 1 1985, 2327-2331.
8. For reviews in radical reactions in organic synthesis, see: (a) Malacria, M. Chem. Rev. 1996, 96, 289-306. (b) Iqbal, J.; Bhatia, B.; Nayyar, N. K. Chem. Rev. 1994, 94, 519-564. (c) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev. 1991, 91, 1237-1286. (d) Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds. Pergamon: Oxford, 1991; Vol. 4, pp 715-831. (e) Curran, D. P. Synthesis 1988, 417-439, and 489-513.
9. For reviews in radical reactions in organic synthesis, see: (a) Malacria, M. Chem. Rev. 1996, 96, 289-306. (b) Iqbal, J.; Bhatia, B.; Nayyar, N. K. Chem. Rev. 1994, 94, 519-564. (c) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev. 1991, 91, 1237-1286. (d) Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds. Pergamon: Oxford, 1991; Vol. 4, pp 715-831. (e) Curran, D. P. Synthesis 1988, 417-439, and 489-513.
10. For reviews in radical reactions in organic synthesis, see: (a) Malacria, M. Chem. Rev. 1996, 96, 289-306. (b) Iqbal, J.; Bhatia, B.; Nayyar, N. K. Chem. Rev. 1994, 94, 519-564. (c) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev. 1991, 91, 1237-1286. (d) Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds. Pergamon: Oxford, 1991; Vol. 4, pp 715-831. (e) Curran, D. P. Synthesis 1988, 417-439, and 489-513.
11. For reviews in radical reactions in organic synthesis, see: (a) Malacria, M. Chem. Rev. 1996, 96, 289-306. (b) Iqbal, J.; Bhatia, B.; Nayyar, N. K. Chem. Rev. 1994, 94, 519-564. (c) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev. 1991, 91, 1237-1286. (d) Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds. Pergamon: Oxford, 1991; Vol. 4, pp 715-831. (e) Curran, D. P. Synthesis 1988, 417-439, and 489-513.
12. For reviews in radical reactions in organic synthesis, see: (a) Malacria, M. Chem. Rev. 1996, 96, 289-306. (b) Iqbal, J.; Bhatia, B.; Nayyar, N. K. Chem. Rev. 1994, 94, 519-564. (c) Jasperse, C. P.; Curran, D. P.; Fevig, T. L. Chem. Rev. 1991, 91, 1237-1286. (d) Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds. Pergamon: Oxford, 1991; Vol. 4, pp 715-831. (e) Curran, D. P. Synthesis 1988, 417-439, and 489-513.
13. Routledge, A.; Abell, C.; Balasubramanian, S. Synlett 1997, 61-62.
14. 2-mediated reactions, see: Molander, G. A.; Harris, C. R. Chem. Rev. 1996, 96, 307-338.
15. For synthesis of indole and benzofuran analogs on solid support via Pd-mediated Heck reaction, see: (a) Yun, W.; Mohan, R. Tetrahedron Lett. 1996, 37, 7189-7192. (b) Zhang, H.; Maryanoff, B. E. J. Org. Chem. 1997, 62, 1804-1809.
16. For synthesis of indole and benzofuran analogs on solid support via Pd-mediated Heck reaction, see: (a) Yun, W.; Mohan, R. Tetrahedron Lett. 1996, 37, 7189-7192. (b) Zhang, H.; Maryanoff, B. E. J. Org. Chem. 1997, 62, 1804-1809.
17. 2-mediated cyclization to generate benzofuran derivatives, see: (a) Inanaga, J.; Ujikawa, O.; Yamaguchi, M. Tetrahedron Lett. 1991, 32, 1737-1740. (b) Molander, G. A.; Harring, L. S. J. Org. Chem. 1990, 55, 6171-6176. (c) Curran, D. P.; Totleben, M. J. J. Am. Chem. Soc. 1992, 114, 6050-6058.
18. 2-mediated cyclization to generate benzofuran derivatives, see: (a) Inanaga, J.; Ujikawa, O.; Yamaguchi, M. Tetrahedron Lett. 1991, 32, 1737-1740. (b) Molander, G. A.; Harring, L. S. J. Org. Chem. 1990, 55, 6171-6176. (c) Curran, D. P.; Totleben, M. J. J. Am. Chem. Soc. 1992, 114, 6050-6058.
19. 2-mediated cyclization to generate benzofuran derivatives, see: (a) Inanaga, J.; Ujikawa, O.; Yamaguchi, M. Tetrahedron Lett. 1991, 32, 1737-1740. (b) Molander, G. A.; Harring, L. S. J. Org. Chem. 1990, 55, 6171-6176. (c) Curran, D. P.; Totleben, M. J. J. Am. Chem. Soc. 1992, 114, 6050-6058.
20. For studies of solution radical cyclizations on related systems using tributyltin hydride, see: (a) Shankaran, K.; Sloan, C. P.; Snieckus, V. Tetrahedron Lett. 1985, 26, 6001-6004. (b) Parker, K. A.; Spero, D. M.; Inman, K. C. Tetrahedron Lett. 1986, 27, 2833-2836. (c) Abeywickrema, A. N.; Beckwith, A. L. J.; Gerba, S. J. Org. Chem. 1987, 52, 4072-4078.
21. For studies of solution radical cyclizations on related systems using tributyltin hydride, see: (a) Shankaran, K.; Sloan, C. P.; Snieckus, V. Tetrahedron Lett. 1985, 26, 6001-6004. (b) Parker, K. A.; Spero, D. M.; Inman, K. C. Tetrahedron Lett. 1986, 27, 2833-2836. (c) Abeywickrema, A. N.; Beckwith, A. L. J.; Gerba, S. J. Org. Chem. 1987, 52, 4072-4078.
22. For studies of solution radical cyclizations on related systems using tributyltin hydride, see: (a) Shankaran, K.; Sloan, C. P.; Snieckus, V. Tetrahedron Lett. 1985, 26, 6001-6004. (b) Parker, K. A.; Spero, D. M.; Inman, K. C. Tetrahedron Lett. 1986, 27, 2833-2836. (c) Abeywickrema, A. N.; Beckwith, A. L. J.; Gerba, S. J. Org. Chem. 1987, 52, 4072-4078.
23. 4, 2-methyl-2-butene, t-BuOH, THF.
24. (a) O'Donnell, M. J.; Zhou, C.; Scott, W. L. J. Am. Chem. Soc. 1996, 118, 6070-6071.
25. (b) Schwesinger, R.; Willaredt, J.; Schlemper, H.; Keller, M.; Schmidt, D.; Fritz, H. Chem. Ber. 1994, 127, 2435-2454.
26. HMPA is essential for the reaction on solid support.
27. Due to the sensitivity of reduced products toward TFA, they are cleaved into their phenol derivatives during removal from resin.
28. Used as supplied by commercial sources. (14) A possible intermediate is: equation presented
29. Zhou, Z.; Bennett, S. M. Tetrahedron Lett. 1997, 38, 1153-1156.
30. Purchased from Argonaut Technologies, Inc.
31. Look, G. C.; Holmes, C. P.; Chinn, J. P.; Gallop, M. A. J. Org. Chem. 1994, 59, 7588-7590.
32. To preclude the amide proton as a possible proton source in solution, we synthesized the ester 8 instead of the benzamide.