Enantioselective reduction enone epoxidation

The reaction between alkyl hydroperoxides and enones has also been carried out using the same catalyst 28c and showing a similar behavior (Scheme 3.31). While the reaction usually leads to the formation of an epoxide as final product, under the optimized conditions and, in particular, by the correct election of the alkyl hydroperoxide nucleophile, the reaction can be directed to the formation of the p-peroxy-substituted ketone product in excellent yields and enantioselectivities. Reduction of these adducts allowed the preparation of the corresponding p-hydroxy ketone, therefore showing that the methodology is suitable for carrying out the formal enantioselective conjugate addition of OH to enones. 

List and coworkers reported an oxa-Michael reaction with aliphatic acyclic enones 94 using hydrogen peroxide as oxygen source [111]. Treatment of enones with catalytic amounts of cinchona alkaloid derived primary amine 33 (as its salt), followed by excess hydrogen peroxide furnished the intermediate peroxy-hemiketals with high yields and stereoselectivities. Subsequent reduction of these compounds led to the corresponding p-hydroxyketones 124 without loss of enantioselectivity (Scheme 33.36). The same research group developed the asymmetric epoxidation of enones with excellent results [112],... 

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