Radical cyclization reaction using a combination of phosphinic acid and a base in aqueous ethanol

Chemistry Letters

Volumn , Issue 2, 2000, Pages 104-105

  Yorimitsu, Hideki ^a   Shinokubo, Hiroshi ^a   Oshima, Koichiro ^a  

^a KYOTO UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0034335964     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.2000.104     Document Type: Article

References (18)

1. D. P. Curran, in "Comprehensive Organic Synthesis," ed by B. M. Trost, I. Fleming, and C. H. Heathcock, Pergamon Press, Oxford (1991), Vol. 4, Chap. 4.1; B. Giese, B. Kopping, T. Gaöbel, J. Dickhaut, G. Thoma, K. J. Kulicke, and F. Trach, Org. React., 48, 301 (1996).
2. D. P. Curran, in "Comprehensive Organic Synthesis," ed by B. M. Trost, I. Fleming, and C. H. Heathcock, Pergamon Press, Oxford (1991), Vol. 4, Chap. 4.1; B. Giese, B. Kopping, T. Gaöbel, J. Dickhaut, G. Thoma, K. J. Kulicke, and F. Trach, Org. React., 48, 301 (1996).
3. For recent review. P. A. Baguley and J. C. Walton, Angew. Chem. Int. Ed. Engl., 37, 3072 (1998).
4. O. Yamazaki, H. Togo, S. Matsubayashi, and M. Yokoyama, Tetrahedron, 55, 3735 (1999); T. Nakamura, H. Yorimitsu, H. Shinokubo, and K. Oshima, Synlett, 1999, 1415.
5. O. Yamazaki, H. Togo, S. Matsubayashi, and M. Yokoyama, Tetrahedron, 55, 3735 (1999); T. Nakamura, H. Yorimitsu, H. Shinokubo, and K. Oshima, Synlett, 1999, 1415.
6. D. H. R. Barton, D. O. Jang, and J. C. Jaszberenyi, J. Org. Chem., 58, 6838 (1993).
7. R. McCague, R. G. Pritchard, R. J. Stoodley, and D. S. Williamson, Chem. Commun., 1998, 2691; S. R. Graham, J. A. Murphy, and D. Coates, Tetrahedron Lett., 40, 2414 (1999); H, Tokuyama, T. Yamashita, M. T. Reding, Y. Kaburagi, and T. Fukuyama, J. Am. Chem Soc., 121, 3791 (1999).
8. R. McCague, R. G. Pritchard, R. J. Stoodley, and D. S. Williamson, Chem. Commun., 1998, 2691; S. R. Graham, J. A. Murphy, and D. Coates, Tetrahedron Lett., 40, 2414 (1999); H, Tokuyama, T. Yamashita, M. T. Reding, Y. Kaburagi, and T. Fukuyama, J. Am. Chem Soc., 121, 3791 (1999).
9. R. McCague, R. G. Pritchard, R. J. Stoodley, and D. S. Williamson, Chem. Commun., 1998, 2691; S. R. Graham, J. A. Murphy, and D. Coates, Tetrahedron Lett., 40, 2414 (1999); H, Tokuyama, T. Yamashita, M. T. Reding, Y. Kaburagi, and T. Fukuyama, J. Am. Chem Soc., 121, 3791 (1999).
10. Reduction of restricted water-soluble substrates in water was reported. D. O. Jang, Tetrahedron Lett., 37, 5367 (1996).
11. In the previous reports using phosphinic acid, reactions were carried out with a base necessarily to protect acid-sensitive functionalities (see Refs. 4 and 5) or to solve a substrate with a carboxylic group into water (see Ref. 6).
12. Phosphorous-centered radical easily adds to terminal olefin (see Ref. 4).
13. K. Nozaki, K. Oshima, and K. Utimoto, Bull. Chem. Soc. Jpn., 64, 403 (1991). Recently, we showed that triethylborane is stable in methanol and acts as an initiator. H. Yorimitsu, T. Nakamura, H. Shinokubo, and K. Oshima, J. Org. Chem., 63, 8604 (1998); T. Nakamura, H. Yorimitsu, H. Shinokubo, and K. Oshima, Synlett, 1998, 1351.
14. K. Nozaki, K. Oshima, and K. Utimoto, Bull. Chem. Soc. Jpn., 64, 403 (1991). Recently, we showed that triethylborane is stable in methanol and acts as an initiator. H. Yorimitsu, T. Nakamura, H. Shinokubo, and K. Oshima, J. Org. Chem., 63, 8604 (1998); T. Nakamura, H. Yorimitsu, H. Shinokubo, and K. Oshima, Synlett, 1998, 1351.
15. K. Nozaki, K. Oshima, and K. Utimoto, Bull. Chem. Soc. Jpn., 64, 403 (1991). Recently, we showed that triethylborane is stable in methanol and acts as an initiator. H. Yorimitsu, T. Nakamura, H. Shinokubo, and K. Oshima, J. Org. Chem., 63, 8604 (1998); T. Nakamura, H. Yorimitsu, H. Shinokubo, and K. Oshima, Synlett, 1998, 1351.
16. 3SnH and a catalytic amount of AIBN in refluxing benzene afforded 2e in 66% yield exclusively after removal of the tin residue with aqueous KF.
17. 3 to a solution of 1d and AIBN gave 2d and 2e in the same ratio. This means direct 6-endo cyclization occurred, that is, the reaction path as below would be improbable. (equation presented)
18. A basic phosphinate solution should be prepared in advance.