enter image description here>enter image description here

If you look at this compound, only the benzylic carbon on the top has a hydrogen attached to it, so how do we oxidize only the top part without touching the lower one (not sure if this product is right), and what happens to the $\ce{-CH2}$ in the middle?

Also, does benzylic oxidation with $\ce{KMnO4}$ happen only with alkyl chains (R)? What if it had a carbonyl instead (a ketone let's say) or any other organic functional group attached to a benzene ring, what would happen to it? For example, Molecule Y here:

enter image description here

Why did it get oxidized to phthalic acid if the lower benzylic carbon doesn't have any hydrogen atoms attached to it?

  • $\begingroup$ Would you like to check this out, also a duplicate of a previously answered question. Also would you mind editing the pictures you've posted to make them more clear? $\endgroup$ Feb 7, 2020 at 18:31
  • $\begingroup$ @SirArthur7 Thanks, honestly Im not that satisfied with the answers on the other questions, I updated the picture, and it still is not clear what happens if what attached to benzene group is cyclic with 1 carbon without benzylic hydrogens like the second picture or contains a carbonyl like the picture i added first clearer $\endgroup$ Feb 7, 2020 at 22:46
  • $\begingroup$ " The abstraction of a benzylic hydrogen atom is consistent with the fact that arenes with no benzylic hydrogens, such as tert-butylbenzene, do not get oxidised. " Then what about my examples? When 1 side has no benzylic hydrogens in the cycle and the other does, logically one side will turn into COOH, what about the other? like the second picture. $\endgroup$ Feb 8, 2020 at 0:08
  • $\begingroup$ Yes sure, your question isn't a duplicate and IMHO the 1st link I gave you wasn't either. The answered question is largely general and there hasn't been much of discussions targeted at specific functional groups. On a different note, can you cite your image sources? It's quite helpful for others to analyse the issue accordingly. As for the post, let's hope someone answers it well :) $\endgroup$ Feb 8, 2020 at 12:38
  • $\begingroup$ @MathewMahindaratne Thank you but this link has already been given to me and it did not answer my question. (Picture 2) $\endgroup$ Feb 8, 2020 at 21:53


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