Chiral aminoborane as a chiral proton source for asymmetric protonation of lithium enolates derived from 2-arylcycloalkanones

(Note: The full text of this document is currently only available in the PDF Version )

Akira Yanagisawa, Hiroshi Inanami and Hisashi Yamamoto


Abstract

Reaction of lithium enolates of 2-arylcycloalkanones 2 with (R,R)-aminoborane 1, prepared from (1R,2R)-1,2-diaminocyclohexane 4 and PhBCl2, gives the corresponding optically active ketones 3 with up to 93% ee; this is the first example of enantioselective protonation using a metal-containing chiral proton source.


References

  1. Reviews: L. Duhamel, P. Duhamel, J.-C. Launay and J.-C. Plaquevent, Bull. Soc. Chim. Fr., 1984, II-421 Search PubMed; C. Fehr, Chimia, 1991, 45, 253; H. Waldmann, Nachr. Chem., Tech. Lab., 1991, 39, 413 CAS; S. Hünig, in Houben-Weyl: Methods of Organic Chemistry; ed. G. Helmchen, R. W. Hoffmann, J. Mulzer and E. Schaumann, Georg Thieme Verlag, Stuttgart, 1995, vol. E 21, p. 3851 Search PubMed; C. Fehr, Angew. Chem., Int. Ed. Engl., 1996, 35, 2566 Search PubMed.
  2. Recent reports: Y. Nakamura, S. Takeuchi, A. Ohira and Y. Ohgo, Tetrahedron Lett., 1996, 37, 2805 Search PubMed; J. Muzart, F. Hénin and S. J. Aboulhoda, Tetrahedron: Asymmetry, 1997, 8, 381 CrossRef CAS; Y. Nakamura, S. Takeuchi, Y. Ohgo, M. Yamaoka, A. Yoshida and K. Mikami, Tetrahedron Lett., 1997, 38, 2709 CrossRef CAS; H. Kosugi, M. Abe, R. Hatsuda, H. Uda and M. Kato, Chem. Commun., 1997, 1857 CrossRef CAS; J. Martin, M.-C. Lasne, J.-C. Plaquevent and L. Duhamel, Tetrahedron Lett., 1997, 38, 7181 RSC.
  3. Enantioselective protonation of silyl enol ethers and ketene silyl acetals: (a) F. Cavelier, S. Gomez, R. Jacquire and J. Verducci, Tetrahedron: Asymmetry, 1993, 4, 2501 CrossRef CAS; (b) F. Cavelier, S. Gomez, R. Jacquire and J. Verducci, Tetrahedron Lett., 1994, 35, 2891 CrossRef CAS; (c) K. Ishihara, M. Kaneeda and H. Yamamoto, J. Am. Chem. Soc., 1994, 116, 11 179 CrossRef CAS; (d) K. Ishihara, S. Nakamura and H. Yamamoto, Croat. Chem. Acta, 1996, 69, 513 Search PubMed; (e) K. Ishihara, S. Nakamura, M. Kaneeda and H. Yamamoto, J. Am. Chem. Soc., 1996, 118, 12854 CrossRef CAS; (f) T. Taniguchi and K. Ogasawara, Tetrahedron Lett., 1997, 38, 6429 CrossRef CAS; (g) M. Takahashi and K. Ogasawara, Tetrahedron: Asymmetry, 1997, 8, 3125 CrossRef CAS; (h) M. Sugiura and T. Nakai, Angew. Chem., Int. Ed. Engl., 1997, 36, 2366 CrossRef CAS.
  4. For examples of simple enolates: (a) H. Hogeveen and L. Zwart, Tetrahedron Lett., 1982, 23, 105 CrossRef CAS; (b) M. B. Eleveld and H. Hogeveen, Tetrahedron Lett., 1986, 27, 631 CrossRef CAS; (c) K. Matsumoto and H. Ohta, Tetrahedron Lett., 1991, 32, 4729 CrossRef CAS; (d) K. Fuji, K. Tanaka and H. Miyamoto, Tetrahedron: Asymmetry, 1993, 4, 247 CrossRef CAS; (e) K. Fuji, T. Kawabata and A. Kuroda, J. Org. Chem., 1995, 60, 1914 CrossRef CAS; (f) T. Takahashi, N. Nakao and T. Koizumi, Chem. Lett., 1996, 207 CAS; (g) H. Kosugi, K. Hoshino and H. Uda, Tetrahedron Lett., 1997, 38, 6861 CrossRef CAS; (h) T. Tsunoda, H. Kaku, M. Nagaku and E. Okuyama, Tetrahedron Lett., 1997, 38, 7759 CrossRef CAS; (i) P. Riviere and K. Koga, Tetrahedron Lett., 1997, 38, 7589 CrossRef CAS; (j) T. Takahashi, N. Nakao and T. Koizumi, Tetrahedron: Asymmetry, 1997, 8, 3293 CrossRef CAS.
  5. M. Vaultier and B. Carboni, in Comprehensive Organometallic Chemistry II, ed. E. W. Abel, F. G. A. Stone and G. Wilkinson, Pergamon, Oxford, 1995, vol. 11, p. 247 Search PubMed.
  6. A review of the preparation of aminoboranes: M. F. Lappert, P. P. Power, A. R. Sanger and R. C. Srivastava, Metal and Metalloid Amides, Ellis Horwood, Chichester, 1980, p. 76 Search PubMed.
  7. Bun Li can be used for cleavage of the Si–O bond of silyl enol ether 5 instead of MeLi. Generation of lithium enolates: E. W. Colvin, Silicon in Organic Synthesis; Butterworth: London, 1981, p. 217 Search PubMed.
  8. A. I. Meyers, D. R. Williams, G. W. Erickson, S. White and M. Druelinger, J. Am. Chem. Soc., 1981, 103, 3081 CrossRef CAS.
Click here to see how this site uses Cookies. View our privacy policy here.