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 have a suggestion that could explain the attacK of electron pair of alkene pi bond to the oxygen of osmium tetroxide : The electron pair of alkene pi bond repels the electron density of the oxygen when the osmium tetroxide approaches the alkene, creating a temporary δ+ on the oxygen that is closer to the pi bond of alkene. The electron-rich alkene then attacks the electron-poor oxygen.

Dimitrios Kariotoglou