# How can you reverse ozonolysis?

Jun 5, 2017

With some difficulty.........

#### Explanation:

With some difficulty in that when ozonolysis is performed, typically we BREAK $C = C$ bonds......i.e.

${R}_{1} {R}_{2} C = C {R}_{3} {R}_{4} \stackrel{{O}_{3}}{\rightarrow} {R}_{2} {R}_{2} C = O + O = C {R}_{3} {R}_{4}$

And for the reverse reaction we have to perform a $C - C$ coupling reaction, a notoriously difficult proposition in organic chemistry.

And thus from an olefin (for instance) ozonolysis gives 2 ketones whose identity could be established by the classical means of chemical analysis: melting points of derivatives. There are quite probably some modern means of organic synthesis that could couple two ketones (the $\text{Mcmurry reaction}$, perhaps, which uses $T i C {l}_{4}$ and $Z n$), anyway you can look this up in your organic text.