Journal of inclusion phenomena

, Volume 2, Issue 1–2, pp 185–194 | Cite as

Dissolving metal reduction K metal-crown ether-toluene system for reductive defluorination

  • Tomihiko Ohsawa
  • Takeshi Oishi
Original Papers


Toluene radical anion, generated by dissolving potassium metal in toluene by the assistance of dicyclohexano-18-crown-6, has been proved to be especially effective for reductive removal of fluorine atom from unactivated alkyl fluorides that resist common reduction conditions. Stereochemical and mechanistic aspects of the present method is discussed. In connection with the preparation of substrates the effect of dipolar aprotic solvents on the nucleophilic fluorination with potassium fluoride/dicyclohexano-18-crown-6 system was also examined, and sulfolane or N,N-dimethyl formamide was shown to be a solvent of choice.


Toluene Fluorine Formamide Radical Anion Reduction Condition 
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References and notes

  1. 1b).
    T. Ohsawa, T. Takagaki, F. Ikehara, Y. Takahashi and T. Oishi,Chem. Pharm. Bull.,30, 3178 (1982).Google Scholar
  2. 2).
    C. J. Pedersen,J. Am. Chem. Soc.,89, 7017 (1967); C. J. Pedersen and H. K. Frensdorff,Angew. Chem. Int. Ed. Engl.,11, 16 (1972).Google Scholar
  3. 3a).
    J.L. Dye, M.G. DeBacker and V.A. Nicely,J. Am. Chem. Soc.,92, 5226 (1970); J.L. Dye, M.T. Lock, F.J. Tehan, R.B. Coolen, N. Papadakis, J.M. Ceraso and M.G. DeBacker,Berichte Bunzenges Phys. Chem.,75, 659 (1971)Google Scholar
  4. 3b).
    J.L. Dye, J.M. Ceraso, M.T. Lock, B.L. Barnett and F.J. Tehan,J. Am. Chem. Soc.,96, 608 (1974); F.J. Tehan, B.L. Barnett and J.L. Dye,ibid. 96, 7203 (1974).Google Scholar
  5. 3c).
    J.L. Dye,Angew. Chem. Int. Ed. Engl. 18, 587 (1979); J.M. Lehn,Pure Appl. Chem. 52, 2303 (1980).Google Scholar
  6. 4).
    U. Schindewolf,Angew. Chem. Int. Ed. Eng l.,7, 190; D.M. Holton, P.P. Edwards, D.C. Johnson, C.J. Page, W. MacFarlane and B. Wood,J. C. S. Chem. Comm.,1984, 741.Google Scholar
  7. 5a).
    A.G.M. Barrett, P.A. Prokopiou and D.H.R. Barton,J. C. S. Perkin Trans. I,1981, 1510. and references cited therein.Google Scholar
  8. 5b).
    H.O. House,Modern Synthetic Reactions, 2nd ed., W.A. Benjamin, Inc., Menlo Park, 1972, pp. 145–227.Google Scholar
  9. 6).
    N.D. Scott, J.F. Walker and V.L. Hansley,J. Am. Chem. Soc.,58, 2442 (1936).Google Scholar
  10. 7).
    B. Kaempf, S. Raynal, A. Collet, F. Schue, S. Boileau and J.-M. Lehn,Angew. Chem. Int. Ed. Engl.,13, 611 (1974); M. Komarynsky and S.I. Weissman,J. Am. Chem. Soc.,97, 1589 (1975); G.V. Nelson and A.V. Zelewsky,ibid.,97, 6279 (1975); P. Belser, G. Desbiolles, U. Ochsenbein and A.V. Zelewsky,Helv. Chim. Acta.,63, 523 (1980).Google Scholar
  11. 8).
    K solution is black-blue and toluene radical anion solution is brown-red in color.Google Scholar
  12. 9).
    Bond energy (Kcal/mol) C−H, 99; C−F, 116; C−Cl, 81; C−Br, 68; C−I, 51. J.B. Hendrickson, D.J. Cram and G.S. Hammond, “Organic Chemistry, 3rd ed.”, McGraw-Hill Kogakusha, Tokyo, 1970, pp 63.Google Scholar
  13. 10a).
    J. Jacobus and J.F. Eastham,J. C. S. Chem. Comm.,1969, 138.Google Scholar
  14. 10b).
    T. Ishihara, E. Ohtani and T. Ando,J. C. S. Chem. Comm.,1975, 367.Google Scholar
  15. 10c).
    R.O. Hutchins, D. Kandasamy, C.A. Maryanoff, D. Masilamani and B.E. Maryanoff,J. Org. Chem.,42, 82 (1977).Google Scholar
  16. 10d).
    M.A. Anbar and E.J. Hart,J. Phys. Chem.,69, 271 (1965).Google Scholar
  17. 11a).
    D. Bryce-Smith, B.J. Wakefield and E.T. Blues,Proceeding Chem. Soc.,1963, 219Google Scholar
  18. 11b).
    J.F. Garst and F.E. Barton II,Tetrahedron Lett.,1969, 587;J. Am. Chem. Soc.,96, 523 (1974); J.F. Garst, R.D. Roberts and B.N. Abels,J. Am. Chem. Soc.,97, 4925 (1975).Google Scholar
  19. 11c).
    J.R. Lacher, A. Kianpour and J.D. Park,J. Phys. Chem.,60, 1454 (1956).Google Scholar
  20. 11d).
    H. Kawasaki, N. Tone and K. Tonomura,Agri. Biol. Chem.,45, 29, 35, 543 (1981).Google Scholar
  21. 12).
    C.L. Liotta and H.P. Harris,J. Am. Chem. Soc.,96, 2250 (1974).Google Scholar
  22. 13).
    P. Ykman and H.K. Hall Jr.Tetrahedron Lett.,1975, 2429.Google Scholar
  23. 14).
    D. Landini and F. Montanari,J. C. S. Chem. Comm.,1974, 879.Google Scholar
  24. 15).
    Half-height width is much narrower at 50 C than at 20 C.Google Scholar
  25. 16).
    18-C-6 or dibenzo-18-C-6 gave poorer results.Google Scholar
  26. 17).
    N.E. Boutin, D.U. Robert and A.R. Cambon,Bull. Soc. Chim. Fr.,1974, 2861; Y. Kobayashi, I. Kumadaki, A. Ohsawa, M. Honda and Y. Hanzawa,Chem. Pharm. Bull.,23, 196 (1975); H.B. Henbest and W.R. Jackson,J. Chem. Soc.,1962, 954; S. Colonna, A. Re, G. Gelbard and E. Cesarotti,J. C. S. Perkin I,1979, 2248.Google Scholar
  27. 18).
    J. Diekman and C. Djerassi,J. Org. Chem.,32, 1005 (1967); O.H. Wheeler and J.L. Mateos,Can. J. Chem.,36, 1431 (1958).Google Scholar
  28. 19).
    O. Diels and P. Blumberg,Chem. Ber.,44, 2847 (1911); J. Mauthner,Monatsh Chem.,30, 635 (1909).Google Scholar
  29. 20).
    Synthesis of (10) was carried out from 24,24-dimethyl-24-hydroxycholane (11) with 70% hydrogen fluoride/pyridine (Aldrich) at ambient temperature in 64% yield. See G.A. Olah, J.T. Welch, Y.D. Vankar, M. Nojima, I. Kerekes and J.A. Olah,J. Org. Chem.,44, 3872 (1979).Google Scholar
  30. 21).
    M.R.C. Gestenberger and A.H. Haas,Angew. Chem. Int. Ed. Engl.,20, 638 (1981); M. Schlosser,Tetrahedron,34, 3 (1978); Ed. by Chem. Soc. Jpn.,Kagaku-Sosetsu,27, “Atarashii Fusso-Kagaku”, Gakkai Shuppan Centre, Tokyo, 1980.Google Scholar
  31. 22).
    Although these solvents have high dielectric constants, they are especially characterized by their low donor numbers which are the indexes of basicity.Google Scholar
  32. 23).
    A.F. Sowinsky and G.M. Whitesides,J. Org. Chem.,44, 2369 (1979).Google Scholar
  33. 24).
    Formation of complex in MeOH in advance, followed by solvent exchange, gave better result than direct reaction in sulfolane.Google Scholar
  34. 25).
    6-Fluoro-l-hexene was reduced under the same conditions to give l-hexene and methylcyclopentane in combined yield of 54–58%, based on alkyl fluoride consumed. See ref. J.F. Garst and F.E. Barton II,Tetrahedron Lett.,1969, 587;J. Am. Chem. Soc.,96, 523 (1974); J.F. Garst, R.D. Roberts and B.N. Abels,J. Am. Chem. Soc.,97, 4925 (1975).Google Scholar
  35. 26).
    L. F. Fieser and M. Fieser,Reagent for Organic synthesis, vol. l, John Wiley and Sons, Inc., New York, 1967, pp. 1102–1103.Google Scholar
  36. 27).
    T. Cuvigny and M. Larcheveque,J. Organomet. Chem.,64, 315 (1974).Google Scholar
  37. 28).
    Terminal vinyl group is easily saturated under K/DC-18-C-6/diglymeiPrOH conditions.Google Scholar
  38. 29).
    A.L.J. Beckwith and G. Moad,J. C. S. Chem. Comm.,1974, 472; C. Walling and A. Cioffari,J. Am. Chem. Soc.,94, 6059 (1972). See also ref 25).Google Scholar
  39. 30).
    J.R. Hanson, H.J. Wadsworth and W.E. Hull,J. C. S. Perkin I,1980, 1382.Google Scholar
  40. 31).
    P.E. Verkade, K.S. de Vries and B.M. Wepster,Rec. Trav. Chem. Pays-Bas,83, 367 (1964).Google Scholar
  41. 32).
    E.J. Corey, M.G. Howell, A. Boston, R.L. Young and R.A. Sneen,J. Am. Chem. Soc.,78, 5036 (1956).Google Scholar
  42. 33).
    Deuterium incorporation study using d8-toluene as solvent or D2O for quenching disclosed that D2O was not incorporated but deuterium in d8-toluene was incorporated to a certain extent. The detail will be reported elsewhere. See also ref. T. Ohsawa, T. Takagaki, A. Haneda and T. Oishi,Tetrahedron Lett.,1981, 2583.Google Scholar

Copyright information

© D. Reidel Publishing Company 1984

Authors and Affiliations

  • Tomihiko Ohsawa
    • 1
  • Takeshi Oishi
    • 1
  1. 1.Riken (The Institute of Physical and Chemical Research)Wako, SaitamaJapan

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