# Attack of HClO4 to dipropylcycloprop-2-en-1-one

What are the products when $$\ce{HClO4}$$ attacks this compound?

I expect $$\ce{HClO4}$$ to protonate the ketone, forming an (aromatic?) carbocation. I don't know where to go from here. Answer suggests formation of butanoic acid and production of $$\ce{CO2}$$. Unsure what really happens here. All hints appreciated.

This question appeared in the JEE 1997.

• That is one very strained system, so once it protonates it is going to rearrange Apr 21, 2020 at 18:38
• @Waylander thanks for your insight - it would be amazing if you could elaborate yourself further; what rearrangement do you see happening? Do you see ring cleavage? Apr 21, 2020 at 18:40
• I wonder where the extra oxygens come from if you are getting butanoic acid and CO2? Presumably the perchloric acid is an aq solution. Apr 21, 2020 at 19:53
• See this prior thread on StackExchange at chemistry.stackexchange.com/questions/31670/… Apr 21, 2020 at 23:57
• AJKOER, I've already seen that question as well as the accepted answer - but I'm unable to see how anything from there could possibly help me with this question.... :( @Waylander If we assume that the acid is an aqueous solution, what do you feel may happen? I'm unable to see what potential difference it could make... Apr 22, 2020 at 6:44

Assuming that your end products are correct I think this reaction would proceed in a similar manner to the way it will proceed if you use hot $$\ce{KMnO4}$$ as a reagent.
The reason I think that is because $$\ce{HClO4}$$ is practically similar to $$\ce{KMnO4}$$ structure and is an even stronger oxidizing agent ($$\ce{Cl^{+7}}$$ is much more unstable (and hence much more willing to oxidize) than $$\ce{Mn^{+7}}$$ ion) which should be able to imitate the behavior of hot $$\ce{KMnO4}$$ reagent (presuming that the greater oxidative strength compensates the level of reactivity $$\ce{KMnO4}$$ shows at a higher temperature)
N.B. :- Here I have presumed that $$\ce{HClO4}$$ can behave similar to hot $$\ce{KMnO4}$$ however I was unable to find a source for that.
• @Rishi it is for $\ce{HIO4}$ and it doesn't suggest that $\ce{HIO4}$ can do oxidative cleavage of alkenes. Jul 8, 2021 at 6:59