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Author Topic: Mechanism in organic  (Read 6666 times)

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Re: Mechanism in organic
« Reply #15 on: November 28, 2009, 10:37:36 AM »

Well, I looked this up and it does seem that the reaction goes through 4 with the retro-Dieckmann leading to the cycloheptane.  Not much info on why you get a mono-acid though.  Very interesting transformation and an unusual one to think about retrosynthetically.  I like it!

Also, I fixed the link in my post above, sorry about that!
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Heory

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Re: Mechanism in organic
« Reply #16 on: November 28, 2009, 11:45:19 PM »

It's reasonable that one ester stayed intact due to higher resonance stability over that of the other ester group.
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Re: Mechanism in organic
« Reply #17 on: November 30, 2009, 05:19:43 AM »

That's a possibility, but these are pretty poor conditions for ester hydrolysis, so I suspect there is something more going on.
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Re: Mechanism in organic
« Reply #18 on: December 01, 2009, 01:48:47 AM »

I think the hydrolysis reaction is quite rational in presence of 1 equ. of DBU.
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Re: Mechanism in organic
« Reply #19 on: December 07, 2009, 06:43:58 AM »

The DBU isn't the problem, it's the one equiv of water giving apparently complete selectivity for hydrolysis of one of the esters.

I dug up another paper that talks about the hydrolysis a little more and it seems that it is often only partial hydrolysis under the reaction conditions and the complete cleavage of the unconjugated ester only occurs during the workup.  The workup is also necessary in some cases to complete the elimination of the beta-hydroxy group.
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