Asymmetric Epoxidation of Homoallylic Alcohols

By: Josephine Nakhla, chemfiles volume 9 article 2

While there are various efficient catalytic systems for the asymmetric epoxidation of allylic alcohols, the extension to homoallylic alcohols had not been demonstrated. While the catalytic system reported above allowed for the desired transformations, the enantioselectivities achieved were a major limitation. After tuning the ligand, Zhang and Yamamoto discovered that the (2,4,6-triethyl)-substituted biphenyl bis(hydroxamic acid) ligand (2) provided the desired epoxide products in excellent yields and enantioselectivities (Scheme 3). In addition, the kinetic resolution of substrate 3 was facilitated by the same catalyst system to afford excellent enantioselectivities of both the chiral homoallylic alcohol as well as the epoxidation product (Scheme 4).1


Scheme 3.


Scheme 4.

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References

  1. Zhang, W.; Yamamoto, H. J. Am. Chem. Soc. 2007, 129, 286.

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