ChiPros Chiral Epoxides

By: Daniel Weibel, Chemfiles Volume 11 Article 1

Oxiranes are very valuable building blocks which allow derivatization:

  • by forming C-X bonds (through reactions with alcohols, ammonia, amines, phenolates etc.)
  • or by forming new C–C bonds (through reactions with cyanide, malonates, allyl silyl reagents, metal-organic reagents, e.g. Mg, Zn, Li organyls)

There are several alternative routes towards chiral aryl-substituted epoxides, among them Jacobsen’s asymmetric epoxidation1 or his hydrolytic kinetic resolution2 method, Sharpless’s asymmetric epoxidation3 using catalytic titan(IV)- isopropylate/diethyl tartrate complexes and tert-butylhydroperoxide, complemented by Shi’s reaction4 using peroxomonosulfate with a chiral ketone as catalyst, or among the enzymatic methods, application of epoxide hydrolases, lipases or monooxygenases. The stereoselective reduction of α-chlorinated acetophenones using dehydrogenases, however, affords a very versatile and more cost-efficient access to a wide range of oxiranes, including both enantiomers of styrene oxide as well as very differently substituted phenyl oxiranes (Scheme 3).


Scheme 3: Stereoselective synthesis of oxiranes.


Aldrich Chemistry is proud to offer ChiPros in small quantities (up to kilograms). A total of 79 products from the ChiPros portfolio are available from Aldrich Chemistry, including chiral amines, alcohols, epoxides and carboxylic acids.

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Materials

     

References

  1. Zhang, W.; Loebach, J. L. et al. J. Am. Chem. Soc. 1990, 112, 2801-2803.
  2. White, D. E.; Jacobsen, E. N. Tetrahedron: Asymmetry 2003, 14, 3633-3638.
  3. (a) Katsuki, T.; Sharpless, K. B. J. Am. Chem. Soc. 1980, 102, 5974-5976. (b) Review: Hüft, E. Top. Curr. Chem. 1993, 164, 63-77.
  4. (a) Wang, Z.-X.; Tu, Y. et al. J. Am. Chem. Soc. 1997, 119, 11224-11235; (b) Ager, D.; Anderson, K. et al., Org. Proc. Res. Dev. 2007, 11, 44-51; (c) Aldrich Chemfiles 2010, 3, 4-5.

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