11. Third, the products of the Sharpless epoxidation frequently have enantiomeric excesses above 90 %. 12. Scopine can be prepared by the hydrolysis of Prilezhaev epoxidation with trifluoroperacetic acid affords scopine. 13. In the first pathway, ( + )-costunolide undergoes enzymatic epoxidation forming parthenolide. 14. This indicates that MupO is either not involved or is not essential for this epoxidation step. 15. Stilbene undergoes reactions typical of alkenes, being susceptible to bromination, epoxidation , and cycloaddition. 16. It can be prepared by epoxidation of styrene with peroxybenzoic acid, in the Prilezhaev reaction: 17. Phase-transfer catalysis of nucleophilic epoxidation is also possible using cinchona-based alkaloid catalysts. 18. Antheraxanthin is a partially de-epoxidized ( see de-epoxidation ) form of violaxanthin. 19. After 1, 4-elimination, the diene undergoes an epoxidation ( Step D ). 20. Furthermore, the enantioselective epoxidation of conjugated dienes is much higher than that of the nonconjugated dienes.
