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Topic: Problem of the Week - 6/22/09  (Read 6908 times)

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Offline azmanam

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Problem of the Week - 6/22/09
« on: June 21, 2009, 11:26:00 PM »
The other question is still up if anyone wants to take a crack at part 2

http://www.chemicalforums.com/index.php?topic=33985.0

But we'll move on, since I think people are tired of that one :)

QUESTION: The following reaction is an example of an 'abnormal Michael addition.'  Provide a mechanism for this reaction that is consistent with the isotope labeling pattern shown.

Again, watch out for that 14C.  It'll throw you.
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Offline orgopete

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Re: Problem of the Week - 6/22/09
« Reply #1 on: June 22, 2009, 11:59:04 PM »
How about a Michael, intramolecular Claisen, and retro-Claisen?
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Offline azmanam

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Re: Problem of the Week - 6/22/09
« Reply #2 on: June 24, 2009, 07:35:21 AM »
yup, that'll do it.  Anyone want to draw up an arrow pushing mechanism?  The intermediate after the intramolecular Claisen is pretty neat looking.
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Offline plankk

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Re: Problem of the Week - 6/22/09
« Reply #3 on: June 24, 2009, 10:04:46 AM »
Neat looking? Maybe you have thought about such product

Offline azmanam

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Re: Problem of the Week - 6/22/09
« Reply #4 on: June 24, 2009, 10:16:10 AM »
no... that's not what the product of the intramolecular Claisen looks like.  Try again.  The intramolecular Claisen may not be as straightforward as it first seems... :)

correction:That is the product of an intramolecular Claisen... just not one that gets to the product drawn.
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Offline plankk

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Re: Problem of the Week - 6/22/09
« Reply #5 on: June 24, 2009, 11:47:01 AM »
So maybe this is the interesting us product of the intramolecular Claisen.

Offline azmanam

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Re: Problem of the Week - 6/22/09
« Reply #6 on: June 24, 2009, 11:50:16 AM »
yup
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