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
Abstract
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
Highly Enantioselective Epoxidation of cis-Olefins by Chiral Dioxirane
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.
Key Words
Epoxides, Organocatalysis, Oxone, Shi Epoxidation
ID: J48-Y1997-750