View PDF Version
 
DOI: 10.1039/A807863G (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 1, 1999, 155-162

The effects of different ester and ketal protecting groups on the reactivity and selectivity of tartrate-derived silylketene acetals

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

Varinder K. Aggarwal, Susannah J. Masters, Harry Adams, Sharon E. Spey, George R. Brown and Alan J. Foubister

Abstract

The reaction of tartrate-derived silylketene acetals and benzaldehyde has been investigated and the yields and diastereoselectivities have been found to be dependent upon the nature of the tartrate ester. Utilising the di-tert-butyl tartrate derivatives, high yields were achieved using a variety of aldehyde substrates. The reactions all proceeded with excellent levels of stereoselectivity ([greater than or equal, slant] 82∶18); the sense of induction being dependent upon the choice of Lewis acid. BF3·OEt2 and TiCl3(OiPr) furnished complementary products in several cases and a model has been proposed to account for this observation.

References

  1. T. Katsuki and K. B. Sharpless, J. Am. Chem. Soc., 1980, 102, 5974 CrossRef CAS.
  2. R. Neaf and D. Seebach, Angew. Chem., Int. Ed. Engl., 1981, 20, 1030 CrossRef.
  3. V. K. Aggarwal, M. F. Wang and A. Zaparucha, J. Chem. Soc., Chem. Commun., 1994, 87 RSC.
  4. For a review of the chemistry biology of the squalestatins see: A. Nadin and K. C. Nicolaou, Angew. Chem., Int. Ed. Engl., 1996, 35, 1622 Search PubMed.
  5. (a) Six total syntheses have been published to date: E. M. Carreira and J. Du Bois, J. Am. Chem. Soc., 1994, 116, 10825 Search PubMed; (b) K. C. Nicolaou, A. Nadin, J. E. Leresche, E. W. Yue and S. La Greca, Angew. Chem., Int. Ed. Engl., 1994, 33, 2190 CrossRef; (c) D. A. Evans, J. C. Barrow, J. L. Leighton, A. J. Robichaud and M. Sefkow, J. Am. Chem. Soc., 1994, 116, 12111 CrossRef CAS; (d) D. Stoermer, S. Caron and C. H. Heathcock, J. Org. Chem., 1996, 61, 9126 CrossRef CAS; (e) H. Sato, S. Nakamura, N. Watanabe and S. Hashimoto, Synlett, 1997, 451 CAS; (f) A. Armstrong, L. H. Jones and P. A. Barsanti, Tetrahedron Lett., 1998, 39, 3337 CrossRef CAS.
  6. T. Mukaiyama, K. Narasaka and K. Banno, Chem. Lett., 1973, 1011 CAS.
  7. A range of Lewis acids including TiCl3(OiPr), Sc(OTf)3 and EtAlCl2 were investigated but BF3·OEt2 afforded the highest yields and selectivities in all cases.
  8. D. A. Evans, B. W. Trotter and J. C. Barrow, Tetrahedron, 1997, 53, 8779 CrossRef CAS.
  9. M. Carmack and C. J. Kelley, J. Org. Chem., 1968, 35, 2171 CrossRef.
  10. NOE enhancements between H1 and H3 could not be obtained due to the close proximity of the 2 signals.
  11. C. H. Heathcock, S. K. Davidsen, K. T. Hug and L. A. Flippin, J. Org. Chem., 1986, 51, 3027 CrossRef CAS.
  12. C. Gennari, in Comprehensive Organic Synthesis, ed. B. M. Trost, Pergamon Press Inc, New York, 1991, vol. 2, p. 629 Search PubMed.
  13. H. E. Zimmerman and M. D. Traxler, J. Am. Chem. Soc., 1956, 79, 1920.
  14. J. A. Musich and H. Rapoport, J. Am. Chem. Soc., 1978, 100, 4865 CrossRef CAS.
  15. S. Zheng and D. Y. Sogah, Tetrahedron, 1997, 53, 15469 CrossRef CAS.
  16. D. Seebach, E. Hungerbühler, R. Naef, P. Schnurrenberger, B. Weidmann and M. Züger, Synthesis, 1982, 138 CrossRef CAS.
  17. G. M. Sheldrick, SHELXL 93, An integrated system for refining crystal structures from diffraction data, University of Gottingen, Germany, 1993.
Click here to see how this site uses Cookies. View our privacy policy here.