An Efficient Catalytic Asymmetric Epoxidation Method
Zhi-Xian Wang, Yong Tu, Michael Frohn, Jian-Rong Zhang and Yian Shi*
*Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, Email: yianlamar.colostate.edu
Z.-X. Wang, Y. Tu, M. Frohn, J.-R. Zhang, Y. Shi, J. Am. Chem. Soc., 1997, 119, 11224-11235.
DOI: 10.1021/ja972272g (free Supporting Information)
A highly effective catalytic asymmetric epoxidation method allows the conversion of trans-disubstituted and trisubstituted olefins using potassium peroxomonosulfate (Oxone) as oxidant and a fructose-derived ketone as catalyst with high enantioselectivies. Functional groups such as tributylsilyl ether, acetal, chloride, and ester are tolerated. Enantiomeric excesses for cis-olefins and terminal olefins are not high yet.
see article for more examples
proposed transition state
H. Tian, X. She, L. Shu, H. Yu, Y. Shi, J. Am. Chem. Soc., 2000, 122, 11551-11552.
B. Wang, O. A. Wong, M.-X. Zhao, Y. Shi, J. Org. Chem., 2008, 73, 9539-9543.