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Topic: Reaction mechanism proposal  (Read 3817 times)

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Offline azncuzin202

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Reaction mechanism proposal
« on: November 30, 2012, 10:04:07 AM »
Can someone help me propose a mechanism for this reaction? I can't seem to figure out how to form a third benzene group? Do i have to break a bond to make the benzene?

Offline orgopete

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Re: Reaction mechanism proposal
« Reply #1 on: November 30, 2012, 10:24:58 AM »
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Offline azncuzin202

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Re: Reaction mechanism proposal
« Reply #2 on: November 30, 2012, 11:06:56 AM »
Yeah I got that far but how do you form the benzene ring?

Offline discodermolide

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Re: Reaction mechanism proposal
« Reply #3 on: November 30, 2012, 11:19:24 AM »
With great difficulty I would imagine, you have a 5 valent carbon in your structure!
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Offline azncuzin202

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Re: Reaction mechanism proposal
« Reply #4 on: November 30, 2012, 11:46:02 AM »
Does the benzene solvent help?

Offline discodermolide

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Re: Reaction mechanism proposal
« Reply #5 on: November 30, 2012, 11:54:17 AM »
With great difficulty I would imagine, you have a 5 valent carbon in your structure!


You still have a 5 valent carbon in your structure.
Benzene will not help the 5 valent carbon.
Please draw the product you want, without a 5 valent carbon.
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Offline azncuzin202

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Re: Reaction mechanism proposal
« Reply #6 on: November 30, 2012, 11:55:29 AM »
The product is in the picture?

Offline discodermolide

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Re: Reaction mechanism proposal
« Reply #7 on: November 30, 2012, 11:57:37 AM »
The product has a carbon atom linked to 5 other carbon atoms. The last time I looked carbon could only bond to 4 other atoms!
So what is the correct structure of your product?
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Offline orgopete

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Re: Reaction mechanism proposal
« Reply #8 on: November 30, 2012, 11:58:28 AM »
Yeah I got that far but how do you form the benzene ring?
Form a benzene ring? No benzene rings are being formed.

Can you follow the Heck to the formation of stilbene? That seems pretty straight forward in the wikipedia mechanism.

@Disco, I presume he simply drew the double bond in the wrong direction. I think this is still a Heck, but double.
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Offline azncuzin202

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Re: Reaction mechanism proposal
« Reply #9 on: November 30, 2012, 12:03:10 PM »
Ok lets change that double bond up so that the carbon-carbon bond above is a double instead. Does that change things? I'm of course referring to the product.

Offline azncuzin202

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Re: Reaction mechanism proposal
« Reply #10 on: November 30, 2012, 12:05:22 PM »

[/quote]
Form?



@Disco, I presume he simply drew the double bond in the wrong direction. I think this is still a Heck, but double.
[/quote]
Yeah sorry about the wrong position of the double bond. I don't believe this happens in one step though?

Offline discodermolide

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Re: Reaction mechanism proposal
« Reply #11 on: November 30, 2012, 12:13:10 PM »
What happens if you have an excess of bromobenzene?.
Look at the link Orgopete provided you with after intensive searching of the internet and giving Prof. Google a headache.
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