# Electron flow: How does osmium tetroxide react with alkenes?

This is a question that has bothered me for some time.I have always thought that the part of one molecule will only attack part of another molecule if it has a higher positive charge.So with this in mind, why does the alkene double bond attack the $\ce{O}$ atom of $\ce{OsO4}$. Isn’t the $\ce{O}$ atom negatively charged?

• I am not sure whether it is the alkene that initiates bond formation. However, take a look at the mechanism. It is a cycloaddition. For all we know, the oxygen from the osmium tetroxide may be the one initiating the formation of the bond. I will try to look some journals and post what I find. – CoffeeIsLife Dec 8 '16 at 4:29
• Not all reactions are driven by simple attraction of oppositely charged atoms. Consider alkene hydrogenation, acetylene trimerization, or the Diels–Alder thing. – Ivan Neretin Dec 8 '16 at 5:59