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4262224 
Journal Article 
Asymmetric epoxidation of (Z)-enol esters catalyzed by titanium(salalen) complex with aqueous hydrogen peroxide 
Matsumoto, K; Feng, C; Handa, S; Oguma, T; Katsuki, T 
2011 
1 
Tetrahedron
ISSN: 0040-4020 
67 
35 
6474-6478 
WOS:000294198300005 
Titanium(salalen) complex 1 was an effective catalyst for asymmetric epoxidation of enol esters. Although (E)-enol esters were reluctant to proceed, (Z)-enol esters underwent asymmetric epoxidation to give the epoxides in high yields with high enantioselectivity ranging from 86 to >99% ee in the presence of aqueous hydrogen peroxide as the stoichiometric oxidant. Complete enantioselectivity was observed in the reaction of (Z)-3,3-dimethylbut-1-en-1-yl 4-methoxybenzoate. The obtained epoxide was readily transformed into the corresponding 1,2-diol by reduction with lithium borohydride without erosion of the high enantiomeric excess. (C) 2011 Elsevier Ltd. All rights reserved. 
Asymmetric reaction; Epoxidation; Hydrogen peroxide; Titanium; Enol ester