Unexpected C-arylation of a gibberellin: A cautionary note on the radical deoxygenation of homoallylic secondary alcohols

Tetrahedron Letters

Volumn 37, Issue 24, 1996, Pages 4255-4258

  Mander, Lewis N ^a   Sherburn, Michael S ^b  

^a AUSTRALIAN NATIONAL UNIVERSITY   (Australia)

^b MASSEY UNIVERSITY   (New Zealand)

Author keywords

[No Author keywords available]

Indexed keywords

ALLYL ALCOHOL; BENZENE; GIBBERELLIN; LACTONE DERIVATIVE; THIONOCARBONATE DERIVATIVE; TRIBUTYLTIN; UNCLASSIFIED DRUG;

ARTICLE; CHEMICAL MODIFICATION; CHEMICAL REACTION; OXIDATION;

EID: 0030012847     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00810-6     Document Type: Article

References (23)

1. Mander, L.N. Chem. Rev., 1992, 92, 573.
2. Mander, L. N.; Owen, D. J. Tetrahedron Lett. 1996, 37, 723-726.
3. Mander, L. N.; Owen, D.J.; Croker, S.J.; Gage, D.A.; Gaskin, P.; Hedden, P.; Lewis, M.J.; Talon, M.; Zeevaart, J.A.D.; Brenner, M.L.; Sheng, C. Phytochemistry, in press.
4. Cross, B.E.; Grove, J.F.; Morrison, A. J. Chem. Soc. 1961, 2498.
5. Kirkwood, P.S.; MacMillan, J.; Sinnott, M.L. J. Chem. Soc., Perkin Trans. 1, 1980, 2117.
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7. Crich, D.; Quintero, L. Chem. Rev., 1989, 89, 1413.
8. Beale, M.H.; MacMillan, J.; Makinson, I.K. Tetrahedron Lett., 1986, 27, 1109.
9. Beale, M.H.; MacMillan, J.; Makinson, I.K.; Willis, C.L. J. Chem. Soc., Perkin Trans. 1, 1991, 1191.
10. Robins, M.J.; Wilson, J.S. J. Am. Chem. Soc., 1981, 103, 932.
11. Robins, M.J.; Wilson, J.S.; Hansske, F. J. Am. Chem. Soc., 1983, 105, 4059.
12. Barton, D.H.R.; Motherwell, W.B.; Stange, A. Synthesis, 1981, 743.
13. 13C nmr, FTIR) as well as HRMS and/or elemental analyses.
14. 3): δ 1.37 (s, 3H, H-18); 1.40 (dd, 1HK, J = 14.5, 1.4Hz, H-15); 1.74 (m, 2H, H-11, H-12); 1.99 (s, 3H, OAc); 2.25 (m, 3H, H-11, H-14, H-15); 2.36 (m, 2H, H-12, H-14); 2.63 (dd, 1H, J = 14.0, 3.6Hz, H-9); 3.30 (d, 1H, J = 5.3 Hz, H-1); 3.44 (d, 1H, J = 3.6 Hz, H-6); 3.68 (s, 3H, OMe); 3.85 (d, 1H, J = 3.6 Hz, H-5); 4.70 (br s, 1H, H-17); 4.78 (d, 1 H, J = 6.4 Hz, H-3); 5.00 (d, 1H, J = 1.7 Hz, H-17); 5.07 (dd, 1H, J = 6.4, 5.3 Hz, H-2); 7.26 (m, 2H, ArH); 7.33 (br t, 1H, J = 8.0Hz, ArH); 7.38 (br t, 1H, J = 8.0Hz, ArH); 7.84 (br d, 1H, J = 7.5Hz, ArH).
15. Mander, L.N.; Sherburn, M.S.; Willis, A.C., submitted to Acta Cryst. C.
16. Sternhell, S. in Dynamic Nuclear Magnetic Resonance Spectroscopy, Jackman, L.M. & Cotton, F.A. eds. Academic Press, New York, 1975, pp 163-201.
17. For such an addition to the aromatic ring to be geometrically possible, an endo-orientation of the phenoxy substituent must be adopted in the initial cyclisation at C-1.
18. Reactions of alkyl radicals with benzene are usually slow (Giese, B. Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds; Pergamon: Oxford, 1986; p 212) but have been witnessed before: Camaggi, C.M.; Leardini, R.; Zanirato, P. J. Org. Chem., 1977, 42, 1570.
19. Reactions of alkyl radicals with benzene are usually slow (Giese, B. Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds; Pergamon: Oxford, 1986; p 212) but have been witnessed before: Camaggi, C.M.; Leardini, R.; Zanirato, P. J. Org. Chem., 1977, 42, 1570.
20. Barton, D.H.R.; Blundell, P.; Dorchak, J.; Jang, D.O.; Jaszberenyi, J.Cs. Tetrahedron, 1991, 47, 8969.
21. Kirkwood, P.S.; MacMillan, J.; Hutchison, M. J. Chem. Soc. 1982, 707.
22. Lombardo, L.; Mander, L.N.; Turner, J.V. J. Am. Chem. Soc. 1980, 102, 6626.
23. An analogous sequence has been reported for the phenyl thionocarbonate of 4-phenyl-3-butenol (M.D. Bachi, M.D.; Bosch, M. J. Org. Chem., 1989, 54, 1234). In this case, however, by virtue of the primary nature of the C-O bond, fragmentation (leading to deoxygenation) would be disfavoured relative to cyclisation. Moreover, there are fewer steric constraints and the radical centre is benzylic in the initial cyclised intermediate (equivalent to B).