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I've just started with EAS. I wanted to write down a mechanism for acylation of a cyclic anhydride (for some reason the formation of the carbocation is not given in my textbook). So I wish to know whether this mechanism is correct or now. Since this is my first attempt at writing one, I don't know whether it's correct.

The reaction:

enter image description here

What I came up with:

enter image description here

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The mechanism shown in the question seems reasonable enough to me. I would note that ring opening before the attack on the $\pi$-system is likely, but not absolutely necessary. Loss of $\ce{AlCl3}$ may not occur until workup. Direct proton transfer seems unlikely, but is a inconsequential detail. Note however, that the electron pushing arrow is drawn opposite to what it needs to be for that transfer.

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    $\begingroup$ I didn't quite understand what you meant by 'workup' $\endgroup$ – Avnish Kabaj Jan 11 '18 at 20:33
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    $\begingroup$ Workup = quenching the reaction usually with ice/water $\endgroup$ – Waylander Jan 12 '18 at 0:38
  • $\begingroup$ are you sure that the top oxygen's lone pair forms the complex and not the middle ones' ? $\endgroup$ – Archer Mar 23 '18 at 15:07
  • $\begingroup$ Seems more likely to me, but the mechanism would then still work. $\endgroup$ – TAR86 Mar 23 '18 at 17:15
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That RED step in the reaction seems to be a little mysterious as to what they have used and how have they got the next product. I would say if one would use a reagent like Zn/Hg + HCl , both the carbonyl groups would be eliminated, and then the next step would be valid in this way:enter image description here

Please correct me if I am wrong anywhere.

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