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Topic: Ozonolysis of Alkenes  (Read 6338 times)

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Offline kelaklub

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Ozonolysis of Alkenes
« on: May 20, 2006, 04:37:15 PM »
The answer to the following question is choice D. I realize this as an Ozonolysis in the first step, but what is the purpose of the Zn in the second part and shouldn't it be incorporated into the product, or is it acting as a catalyst? Thanks.


Offline Albert

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Re: Ozonolysis of Alkenes
« Reply #1 on: May 20, 2006, 04:44:04 PM »
Yes, Zn is oxidized to ZnO and you can call this kind of reaction an ozonolysis with  reductive work-up.

However, I think the exercise wants to focus on the two 'main' products (those you actually want to yield by performing the reaction).

Offline kelaklub

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Re: Ozonolysis of Alkenes
« Reply #2 on: May 20, 2006, 05:20:32 PM »
OK. Thanks.

Offline Dan

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Re: Ozonolysis of Alkenes
« Reply #3 on: May 20, 2006, 08:33:09 PM »
Side note, Me2S is also used instead of Zn, so don't be suprised if you see it in an ozonolysis Q.
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Offline Will

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Re: Ozonolysis of Alkenes
« Reply #4 on: May 21, 2006, 06:11:39 AM »
Another side note! H2O2 can be used in the work up to give the corresponding carboxylic acids, and if a reducing agent like NaBH4 (Zn isn't strong enough) is used then you will get the corresponding alcohol.
Like Dan said, dimethylsulfide ((CH3)2S) is used to get the corresponding carbonyl (aldehyde/ketone) compounds. I would say dimethylsulfide is a more common reagent for this purpose, than Zn.

Offline movies

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Re: Ozonolysis of Alkenes
« Reply #5 on: May 22, 2006, 03:53:58 PM »
Another relatively common reagent for a reductive work-up is PPh3.  It works the same way as Me2S and gives the two carbonyl products.

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