The Shi Asymmetric Epoxidation allows the synthesis of epoxides from alkenes using a fructose-derived organocatalyst with Oxone.
Reaction mechanism:
1. Oxidation of the catalyst with Oxone to generate the active epoxidation reagent.
2. The resulting sulfate intermediate is a good leaving group that facilitates the ring closure to the corresponding dioxirane intermediate.
3. The dioxirane derivative induces then the asymmetric epoxidation of the alkene, while regenerating the ketone for the next catalytic cycle.
References:
NROChemistry: https://nrochemistry.com/shi-epoxidation/
Example #1: J. Am. Chem. Soc. 2021, 143, 699. https://doi.org/10.1021/jacs.0c12998
