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Topic: PPA  (Read 13007 times)

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Offline eureka123

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PPA
« on: November 01, 2009, 10:10:40 PM »
I have no clue about this question....
Plz discuss this one...
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Offline Ulfsaar

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Re: PPA
« Reply #1 on: November 01, 2009, 10:21:46 PM »
As this mechanism in my figure
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Offline orgopete

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Re: PPA
« Reply #2 on: November 02, 2009, 12:34:29 AM »
Check your atom count.
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Offline Ulfsaar

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Re: PPA
« Reply #3 on: November 02, 2009, 02:10:45 AM »
Sorry,the correct figure has been upload
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Offline orgopete

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Re: PPA
« Reply #4 on: November 02, 2009, 02:43:08 AM »
If you have in intramolecular reaction of 15 carbons, shouldn't the product also contain 15 carbons?
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Offline eureka123

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Re: PPA
« Reply #5 on: November 02, 2009, 10:03:32 AM »
Sorry but options are
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Offline eureka123

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Re: PPA
« Reply #6 on: November 02, 2009, 10:04:37 AM »
I also found this...can anyone explain this all ?

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Offline movies

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Re: PPA
« Reply #7 on: November 02, 2009, 06:05:27 PM »
Eureka, are you sure you drew those structures right?  I am pretty certain that the product is not one of the two that you drew (close, but not exactly what you drew).
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Offline eureka123

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Re: PPA
« Reply #8 on: November 02, 2009, 09:32:55 PM »
Yes sir,
These are the 2 options..

 but the book may be wrong also..


btw plz explain that abstract from a book which I gave in my last post
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Offline movies

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Re: PPA
« Reply #9 on: November 03, 2009, 04:50:31 PM »
Well, my issue with those two answers is that the first would require an overall oxidation of the substrate, and the second would require the loss of a carbon.  First off, PPA is not really an oxidant.  Second, the loss of a carbon is possible, but I would say unlikely under these conditions with this substrate.

The excerpt from the book is kind of an overview of PPA's common uses, but I don't think it is super useful in the context of this question.

What is the context of this question in the book?  What chapter is it from?
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Offline eureka123

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Re: PPA
« Reply #10 on: November 03, 2009, 10:20:28 PM »
Sir ,that abstract is from a book named "Challenges in synthetic organic chemistry"
in chapter "Dehydration reactions "

So whats the final answer anyway ??
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Offline orgopete

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Re: PPA
« Reply #11 on: November 03, 2009, 11:36:28 PM »
The following seems a logical path.
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Offline eureka123

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Re: PPA
« Reply #12 on: November 04, 2009, 03:16:09 AM »
Any comments on what our friend "orgopete" has done ?
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Offline movies

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Re: PPA
« Reply #13 on: November 04, 2009, 01:34:42 PM »
I think organopete has the right product, but the mechanism is missing a little subtlety.  I don't want to give it away though – any guesses?
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Offline Scatter

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Re: PPA
« Reply #14 on: November 04, 2009, 03:56:25 PM »
Not really.  I'm curious though.  Does it have to do with the placement of the carbocations?
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