Sharpless asymmetric dihydroxylation



Sharpless asymmetric dihydroxylation (also called the Sharpless bishydroxylation) is the chemical reaction of an diol.[1][2][3]

 

It is common practice to perform this reaction using a catalytic amount of osmium tetroxide, which after reaction is regenerated with either AD-mix") The mixture containing (DHQ)2-PHAL is called AD-mix-α, and the mixture containing (DHQD)2-PHAL is called AD-mix-β.[8]

Such chiral diols are important in Nobel Prize in Chemistry.

Reaction mechanism

The reaction mechanism of the Sharpless dihydroxylation begins with the formation of the osmium tetroxide - ligand complex (2). A [3+2]-cycloaddition with the alkene (3) gives the cyclic intermediate 4.[9][10] Basic hydrolysis liberates the diol (5) and the reduced osmate (6). Finally, the stoichiometric oxidant regenerates the osmium tetroxide - ligand complex (2).

Examples

The first step in the synthesis of azasugar 6 is a dihydroxylation reaction[11] of the nucleophilic substitution of bromine by the hydroxyl group in step 2.

For another example of this reaction see: Kuwajima Taxol total synthesis

References

  1. ^ Jacobsen, E. N.; Marko, I.; Mungall, W. S.; Schroeder, G.; Sharpless, K. B. J. Am. Chem. Soc. 1988, 110, 1968. (doi:10.1021/ja00214a053)
  2. ^ Kolb, H. C.; Van Nieuwenhze, M. S.; Sharpless, K. B. Chem. Rev. 1994, 94, 2483-2547. (Review) (doi:10.1021/cr00032a009)
  3. ^ Gonzalez, J.; Aurigemma, C.; Truesdale, L. Org. Syn., Coll. Vol. 10, p.603 (2004); Vol. 79, p.93 (2002). (Article)
  4. ^ Minato, M.; Yamamoto, K.; Tsuji, J. J. Org. Chem. 1990, 55, 766-768. (doi:10.1021/jo00289a066)
  5. ^ Oi, R.; Sharpless, K. B. Org. Syn., Coll. Vol. 9, p.251 (1998); Vol. 73, p.1 (1996). (Article)
  6. ^ VanRheenen, V.; Kelly, R. C.; Cha, D. Y. Tetrahedron Lett. 1976, 1973-1976.
  7. ^ McKee, B. H.; Gilheany, D. G.; Sharpless, K. B. Org. Syn., Coll. Vol. 9, p.383 (1998); Vol. 70, p.47 (1992). (Article)
  8. ^ Sharpless, K. B., et al. J. Org. Chem. 1992, 57, 2768-2771. (doi:10.1021/jo00036a003)
  9. ^ Tetrahedron Lett. 1996, 37, 4899-4902.
  10. ^ DelMonte, A. J.; Haller, J.; Houk, K. N.; Sharpless, K. B.; Singleton, D. A.; Strassner, T.; Thomas, A. A. J. Am. Chem. Soc. 1997, 119, 9907-9908. (doi:10.1021/ja971650e)
  11. ^ Efficient asymmetric synthesis of an azasugar in water Ulf M. Lindström, Rui Ding, Olle Hidestål Chemical Communications 2005, 1773.

See also

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sharpless_asymmetric_dihydroxylation". A list of authors is available in Wikipedia.