Advertisement

Vitamin B12, Catalyst of Radical Reactions in Organic Synthesis

  • R. Scheffold
  • S. Busato
  • E. Eichenberger
  • R. Härter
  • H. Su
  • O. Tinembart
  • L. Walder
  • Ch. Weymuth
  • Z. -D. Zhang

Abstract

Vitamin B12 and related metal complexes act as mediators in the electron transfer from the electron source (chemical reducing agent or cathode in electrochemical reductions) to an electrophilic substrate R-X (R-X = alkyl-, vinyl- or acyl- derivative) [1]. On B12-catalyzed reduction R-X is transformed to the radical R. or the carbanion R (depending on the structure of R and the reaction conditions) either directly or via an organometallic intermediate. The Co,C-bond of the organocobalamin intermediate is cleaved as a consequence of redox-reactions [2], thermic or photochemical activation [3].

Keywords

Tartaric Acid Electrochemical Reduction Electron Source Asymmetric Catalysis Electrophilic Substrate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. [1] a)
    R. Scheffold, Nachr.Chem.Tech.Lab. 36, 261 (1988);CrossRefGoogle Scholar
  2. [1] b)
    R. Scheffold S. Abrecht, R. Orlinski, H.R. Ruf, P. Stamouli, O. Tinembart, L. Walder, Ch. Weymuth, Pure & Appl. Chem. 59, 363 (1987);CrossRefGoogle Scholar
  3. [1] c)
    R. Scheffold, Chimia 39, 203 (1985).Google Scholar
  4. [2]
    R. Scheffold, G. Rytz, L. Wälder in “Modern Synthetic Methods” Ed. R. Scheffold, Vol. 3: Salle, Frankfurt/ Sauerländer, Aarau/ Wiley, London p. 355–440, 1983.Google Scholar
  5. [3]
    L. Walder, R. Orlinski, Organometallics 6, 1606 (1987).CrossRefGoogle Scholar
  6. [4]
    R. Scheffold, R. Orlinski, J.Am.Chem.Soc. 102, 7200 (1983).CrossRefGoogle Scholar
  7. [5]
    R. Scheffold, M. Dike, S. Dike, T. Herold, L. Walder, J.Am.Chem.Soc. 102, 3642 (1980).CrossRefGoogle Scholar
  8. [6]
    R. Scheffold, E. Amble, Angew.Chem. 92, 643 (1980); Int.Ed. 19, 629 (1980).CrossRefGoogle Scholar
  9. [7]
    L. Walder, G. Rytz, K. Meier, R. Scheffold, Helv.Chim.Acta 61, 3013 (1978).CrossRefGoogle Scholar
  10. [8]
    H. Su, R. Scheffold, unpublished; to bee publ. in Helv.Chim.Acta (1988).Google Scholar
  11. [9]
    A. Fischli, T.S. Wan, Helv.Chim.Acta 67, 684, 1461, 1883 (1984).CrossRefGoogle Scholar
  12. [10]
    S. Husi, Ch. Weymuth, R. Scheffold, unpubl.; to be publ. in Helv.Chim.Acta (1988).Google Scholar
  13. [11] a)
    B. Giese “Radicals in Organic Synthesis: Formation of Carbon-Carbon Bonds, Org. Chem. Series, Vol. 5, Pergamon Press, Oxford 1986; G. Stork, Bull.Chem.Soc. Jpn. 61, 149 (1988).Google Scholar
  14. [12]
    J.J. Partridge, N.K. Chadha, M.R. Uskokovic, J.Am.Chem.Soc. 95, 7171 (1973).CrossRefGoogle Scholar
  15. [13]
    S. Busato, O. Tinembart, R. Scheffold, unpubl.; to be publ. in Helv.Chim.Acta.Google Scholar
  16. [14]
    R. Härter, Ch. Weymuth, R. Scheffold, unpubl.; to be publ. in Helv.Chim.Acta.Google Scholar
  17. [15]
    A.E. Greene, A.A. Serra, E.J. Barreiro, P.R.R. Costa, J.Org.Chem. 51, 4250 (1987).CrossRefGoogle Scholar
  18. [16]
    G.E. Keck, D.A. Burnett, J.Org.Chem. 52, 2959 (1987); G. Stork, P.M. Sher, H.-L. Chen, J.Am.Chem.Soc. 108, 6384 TT986). [17] H. Su, L. Walder, Z.-D. Zhang, R. Scheffold, Helv.Chim.Acta, in print (1988).Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • R. Scheffold
    • 1
  • S. Busato
    • 1
  • E. Eichenberger
    • 1
  • R. Härter
    • 1
  • H. Su
    • 1
  • O. Tinembart
    • 1
  • L. Walder
    • 1
  • Ch. Weymuth
    • 1
  • Z. -D. Zhang
    • 1
  1. 1.Institute of Organic ChemistryUniversity of BernBernSwitzerland

Personalised recommendations