To run the epoxidation in a stereoespecific manner, I think Sharpless epoxidation doesn' t work well for styrene, to obtain high yield and good enantioselectivity an homoalillyc alcohol is needed for this kind of asymmetric epoxidation.
A better option is to run a hydrolytic kinetic resolution of the terminal racemic epoxide catalyzed but chiral salen Co complexe, the yield must be less than 50% but the ee should be around 99%.
The styrene oxide is commercial available and "cheap".
Another way to obtain this compound in an enantioselective manner is performing the asymmetric reduction of the corresponding alfa bromo ketone, using a chiral boron reagent such as an oxazaborolidine developed by Corey.
Sorry for my poor english and the ortographically mistakes!!