Ozonolysis: Ozonide Formation

Animated mechanism of ozonolysis, showing the stepwise addition of ozone to the alkene 3-methyl-2-pentene and subsequent rearrangement to form the stable ozonide intermediate.

1. Ozone initially adds to the alkene in a concerted process to form an unstable molozonide, which contains two O-O bonds.
2. The molozonide rapidly decomposes, forming a carbonyl compound and a reactive carbonyl oxide intermediate. The carbonyl oxide intermediate contains a highly nucleophilic terminal oxygen, as seen in the electrostatic surface (red = electron-rich).
3. This nucleophilic oxygen attacks the electron-deficient carbon of the carbonyl compound, forming the more stable ozonide.

The ozonide intermediate can then be converted to carbonyl products through reductive or oxidative workup, though this step is not shown in the animation.