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DOI: 10.1039/A703698A (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1997, 2719-2724

Kinetics of the direct borane reduction of pinacolone in THF

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Holger Jockel and Reinhard Schmidt

Abstract

The kinetics of the borane reduction of the ketone pinacolone in THF depend strongly on the borane reagent. NaBH4, which is present in commercial BH3–THF as stabilizer, strongly catalyzes the reaction. The use of commercial BH3–THF results in the borane reaction order of 1.6. In contrast, freshly prepared, pure BH3–THF yields kinetics for which the main reaction, the reduction of the ketone by BH3–THF forming the monoalkoxyborane, are first order in both reactants. Two further subsequent reactions have to be included in the reaction scheme in order to fit the kinetics by numerical integration. Results of semiempirical calculations are compared with experimental findings to eludicate the possible reaction mechanism of the main reaction.

References

  1. S. Itsuno, K. Ito, A. Hirao and S. J. Nakahame, J. Chem. Soc., Chem. Commun., 1983, 469 RSC.
  2. E. J. Corey, R. K. Bakshi and S. J. Shibata, J. Am. Chem. Soc., 1987, 109, 5551 CrossRef CAS.
  3. L. Deloux and M. Srebnik, Chem. Rev., 1993, 93, 763 CrossRef CAS.
  4. S. Wallbaum and J. Martens, Tetrahedron: Asymmetry, 1992, 3, 1475 CrossRef CAS.
  5. J. R. Elliot, W. L. Roth, G. F. Roedel and E. M. Boldebuck, J. Am. Chem. Soc., 1952, 74, 5211 CrossRef.
  6. B. Rice, J. A. Livasy and G. W. Schaeffer, J. Am. Chem. Soc., 1955, 77, 2750 CrossRef CAS.
  7. H. C. Brown and B. C. S. Rao, J. Am. Chem. Soc., 1960, 82, 681 CrossRef CAS.
  8. J. D. Pasto and B. Lepeska, J. Am. Chem. Soc., 1976, 98, 1091 CrossRef.
  9. J. Klein and E. Dunkelblum, Tetrahedron, 1967, 23, 205 CrossRef CAS.
  10. H. C. Brown, Hydroboration, W. A. Benjamin Inc., New York, 1962, p. 18 Search PubMed.
  11. G. Freeguard and L. H. Long, Chem. Ind. (London), 1963, 471.
  12. E. Breuer, Tetrahedron Lett., 1967, 20, 1849 CrossRef.
  13. K. M. Biswar and A. H. Jackson, J. Chem. Soc. (C), 1970, 1667 Search PubMed.
  14. J. D. Pasto, V. Balasubramaniyan and P. W. Wojitkowski, Inorg. Chem., 1969, 8, 594 CrossRef.
  15. J. D. Pasto, B. Lepeska and T. C. Cheng, J. Am. Chem. Soc., 1972, 94, 6083 CrossRef.
  16. H. C. Brown, H. I. Schlesinger and A. B. Burg, J. Am. Chem. Soc., 1939, 61, 673 CrossRef CAS.
  17. R. B. Wetherill, H. C. Brown and B. C. S. Rao, J. Org. Chem., 1957, 22, 1135.
  18. HyperChem software package release 4.5, 1995, Hypercube, Inc., Waterloo, Ontario.
  19. H. C. Brown, Organic Synthesis via Boranes, Wiley, New York, 1974, p. 241 Search PubMed.
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