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I came across this today

An ester $\ce{C4H8O2}$ on reaction with $\ce{CH3MgCl} $ and hydrolysis gives an alcohol. The alcohol on reaction with $\ce{NaOCl}$ and $\ce{H3O+}$ gives acetic acid. Identify the structure of the ester.

But what I'm facing a problem with is the role of $\ce{NaOCl}$. My teacher said it can cleave and oxidize a tertiary alcohol, say tert-butyl alcohol, to acetic acid.

But I couldn't understand the mechanism. Any help will be appreciated.

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  • $\begingroup$ There are not so many possibilities for your ester that yield an alcohol which could be oxidized to acetic acid. Which esters could you imagine from $\ce{C4H8O2}$? $\endgroup$ – pH13 - Yet another Philipp Sep 3 '15 at 10:02
  • $\begingroup$ My problem is not with the ester...but how will NaOCl oxidize the the alcohol obtained...the mechanism.. $\endgroup$ – user14857 Sep 3 '15 at 10:04
  • $\begingroup$ I don't see any evidence in SciFinder that this is an actual transformation. Can you confirm with your teacher that a simple tertiary alcohol can be oxidized to an acid? $\endgroup$ – jerepierre Sep 3 '15 at 20:30
  • $\begingroup$ I actually think you are misinterpreting the problem, but I'll wait for confirmation about the tertiary alcohol oxidation. $\endgroup$ – jerepierre Sep 3 '15 at 20:32
  • $\begingroup$ @jerepierre Maybe i misinterpreted what my teacher said.But it will take atleast a week before i can confirm with him.But what why did you say i'm "misinterpreting" the problem?What do you think will be the solution?What is the particular ester C4H8O2 according to you?What will be NaOCl mechanism according to you?Maybe i'm having a conceptual problem...but its always good to discuss :-) $\endgroup$ – user14857 Sep 4 '15 at 12:58
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Reaction of an ester with a Grignard reagent gives two products: (1) a tertiary alcohol coming from the carbonyl carbon and two equivalents of the Grignard reagent and (2) an alcohol liberated from the ester. I believe it's this liberated alcohol that is reacting with bleach, since a tertiary alcohol is typically resistant to oxidation. However, the liberated alcohol might be primary, secondary, or tertiary depending on the identity of R2.

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The information given says that after treatment with bleach, acetic acid is formed. This tells us two things: (1) that liberated alcohol is a primary alcohol, since the oxidation goes all the way to an acid and (2) that liberated alcohol has two carbons, since acetic acid has two carbons. That implies that the liberated alcohol is ethanol. The starting ester has four carbons total, which leaves two carbons for the carboxy fragment. The original ester was ethyl acetate.

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