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Topic: Hydrogenation of aromatic compd  (Read 3835 times)

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Offline jlee808

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Hydrogenation of aromatic compd
« on: December 20, 2011, 10:53:08 AM »
Have this problem here hoping some of you could shine a lite into it.


I was thininking Birch reduction because that's the only thing about aromatic rings reduction that was in lecture but don't know how to reduce it totally  :-X.
Thanks for any suggestion guys

Offline discodermolide

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Re: Hydrogenation of aromatic compd
« Reply #1 on: December 20, 2011, 11:30:16 AM »
Have this problem here hoping some of you could shine a lite into it.


I was thininking Birch reduction because that's the only thing about aromatic rings reduction that was in lecture but don't know how to reduce it totally  :-X.
Thanks for any suggestion guys

Look up Nishimura's catalyst.
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Offline jlee808

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Re: Hydrogenation of aromatic compd
« Reply #2 on: December 20, 2011, 12:08:12 PM »
Looked up Nishimura's not much info on google. Not in my book. I could see briefly that it reduce the aromatic ring down. but would it affect the Ome?

If I used Birch reduction and follow this:


What would I do next to get my product?
« Last Edit: December 20, 2011, 12:21:03 PM by jlee808 »

Offline discodermolide

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Re: Hydrogenation of aromatic compd
« Reply #3 on: December 20, 2011, 02:03:13 PM »
Looked up Nishimura's not much info on google. Not in my book. I could see briefly that it reduce the aromatic ring down. but would it affect the Ome?

If I used Birch reduction and follow this:


What would I do next to get my product?

3-methylanisole is commercially available. Nishimura's catalyst should not touch the methoxy group. Look at Houben-Weyl's volume on hydrogenation.
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Offline Arctic-Nation

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Re: Hydrogenation of aromatic compd
« Reply #4 on: December 21, 2011, 12:53:14 PM »
I'm not sure you're being very helpful here, disco. ;)

As long as this is a theoretical problem, I'd do something like demethylation (ether cleavage with HI or BBr3), followed by reduction to cyclohexanol over a rhodium catalyst, and then reoxidation to the ketone. Standard textbook reactions.

Offline discodermolide

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Re: Hydrogenation of aromatic compd
« Reply #5 on: December 21, 2011, 03:55:16 PM »
I'm not sure you're being very helpful here, disco. ;)

As long as this is a theoretical problem, I'd do something like demethylation (ether cleavage with HI or BBr3), followed by reduction to cyclohexanol over a rhodium catalyst, and then reoxidation to the ketone. Standard textbook reactions.

The questioner asked about the total reduction of aromatic rings, Nishimura's catalyst is a mixture of rhodium on alumina and does the job.
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Offline fledarmus

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Re: Hydrogenation of aromatic compd
« Reply #6 on: December 21, 2011, 03:56:41 PM »
Still needs a meta-methylation and an ether cleavage...

Offline discodermolide

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Re: Hydrogenation of aromatic compd
« Reply #7 on: December 21, 2011, 03:58:38 PM »
Still needs a meta-methylation and an ether cleavage...

He did not ask for that!
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Offline orgopete

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Re: Hydrogenation of aromatic compd
« Reply #8 on: December 21, 2011, 04:08:25 PM »
I don't want to tip this off just yet, but since poster mentioned Birch reduction, this looks like a Birch reduction problem.

Hint, last step looks like a Gilman addition.
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