The chemistry and reactivity of aryl radicals - The C-C bond formation from o-bromobenzylphenylethers with tin hydride and azobisisobutyronitrile

Tetrahedron

Volumn 53, Issue 1, 1997, Pages 285-298

  Rosa, Ana M ^a   Lobo, Ana M ^a   Branco, Paula S ^a   Prabhakar, Sundaresan ^a  

^a UNINOVA   (Portugal)

Author keywords

[No Author keywords available]

Indexed keywords

DIBENZO[B,D]PYRAN DERIVATIVE; PYRAN DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; DRUG SYNTHESIS; PRIORITY JOURNAL; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0031060193     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4020(96)00984-2     Document Type: Article

References (24)

1. Rosa, A. M.; Prabhakar, S.; Lobo, A. M. Tetrahedron Lett., 1990, 13, 1881 and the preceding paper.
2. Bringmann, G.; Jansen, R. J. Tetrahedron Lett., 1984, 25, 2537.
3. Bringmann, G.; Jansen, R. J. Heterocycles, 1989, 28, 137.
4. Lipshutz, B. H.; Kayser, F.; Maullin, N. Tetrahedron Lett., 1994, 35, 815.
5. a) For the application of radicals to organic synthesis see: Motherwell, W. B.; Crich, D. Free Radical Chain Reactions in Organic Synthesis; Academic Press: London, 1991; Jasperse, C.P.; Curran, D. P.; Fevig, T. L. Chem. Rev., 1991, 91, 1237.
6. a) For the application of radicals to organic synthesis see: Motherwell, W. B.; Crich, D. Free Radical Chain Reactions in Organic Synthesis; Academic Press: London, 1991; Jasperse, C.P.; Curran, D. P.; Fevig, T. L. Chem. Rev., 1991, 91, 1237.
7. b) For a wealth of information pertaining to free radical chain reaction, including bond dissociation energies, succinctly summarised, see: Laird, E. R.; Jorgensen, W. L. J. Org. Chem. 1990, 55, 9.
8. c) For geometric reasons the σ radical formed from an appropriate allylphenylether is reported to afford exclusively the product of 1,5 addition despite the presence of a substituent on the carbon undergoing the attack (Beckwith, A. L. J. Tetrahedron, 1981, 37, 3073).
9. Firestone, R. A. J. Org. Chem., 1969, 9, 2621.
10. The exact mechanism of the oxidation still remains to be clarified. For a study on the subject see: Bowman, W. R.; Heaney, H.; Jordan, B. M. Tetrahedron, 1991, 47, 10119;
11. Beckwith, A. L. J.; Storey, J. M. J. Chem. Soc., Chem. Commun., 1995, 977 and the preceding paper.
12. Demethoxylation in 2′-methoxyphenyl-2-carboxylic acid and its carboxyamide derivative is reported under oxidative conditions: Davies, D. I.; Waring, C. J. J. Chem. Soc., Perkin Trans. 2, 1972, 778; Hey, D. H.; Jones, G. H.; Perkin, M. J. J. Chem. Soc., Perkin Trans 1, 1972, 105.
13. Demethoxylation in 2′-methoxyphenyl-2-carboxylic acid and its carboxyamide derivative is reported under oxidative conditions: Davies, D. I.; Waring, C. J. J. Chem. Soc., Perkin Trans. 2, 1972, 778; Hey, D. H.; Jones, G. H.; Perkin, M. J. J. Chem. Soc., Perkin Trans 1, 1972, 105.
14. Bowman, W. R.; Brown, D. S; Burns, C. A.; Marples, B. A.; Zaidi, N. A. Tetrahedron, 1992, 48, 6883.
15. Curran, D. P. In Comprehensive Organic Synthesis; Trost, B. M.; Fleming, I., Ed.; Pergamon Press: Oxford, 1991; vol. 4; pp. 766.
16. • radical, see: Leardini, R.; Nanni, D.; Pedulli, G. F.; Tundo, A.; Zanardi, G. J. Chem. Soc., Perkin Trans. 1, 1986, 1591.
17. a) A possible reason for the preponderance of the phenol 9 over the pyran 2h could be that the formation of the latter requires an external entity, to remove the hydrogen from a sterically crowded environment, thus diminishing significantly the rate of oxidation relative to the reaction leading to 9.
18. b) Rynard, C. M.; Thankachan, C.; Tidwell, T. T. J. Am. Chem. Soc., 1979, 101, 1196.
19. a) A 1,2-oxygen migration involving the alkyloxygen of an acetate α to a carbon radical in a steroidal compound has been reported:
20. b) Kocovsky, P.; Stary, I.; Turecek, F. Tetrahedron Lett., 1986, 27, 1513. For an alternative explanation see: Beckwith, A. L. J.; Duggan, P. J. J. J. Chem. Soc., Chem. Commun., 1988, 1000.
21. b) Kocovsky, P.; Stary, I.; Turecek, F. Tetrahedron Lett., 1986, 27, 1513. For an alternative explanation see: Beckwith, A. L. J.; Duggan, P. J. J. J. Chem. Soc., Chem. Commun., 1988, 1000.
22. b) For an example of an intramolecular alkoxyl radical addition to an isolated double bond before its quenching by TBTH see ref. 5a, pp. 167.
23. For a reference to incursion of reversibility in an intramolecular aryl-aryl radical reaction, not involving the o radical stabilised by an adjacent EWG group, see: Benati, L.; Montevecchi, P. C.; Tundo, A. J. Chem. Soc., Chem. Commun., 1978, 530.
24. Ames, D. E.; Opalko, A. Tetrahedron, 1984, 40, 1919.