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Topic: a case of aldol condensation?  (Read 5170 times)

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a case of aldol condensation?
« on: September 08, 2004, 09:50:43 AM »
How do you get this from the cyclohexanone?
If you use the aldol cross-condensation there may be a mixture of products? Do you think you have to use a longer route or is it OK?

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Re:a case of aldol condensation?
« Reply #1 on: September 08, 2004, 10:07:36 AM »
How the heck do I insert a gif/jpg? I click on the Attach and it won't show.

THIS is a 2-(1-hydroxyethyl)-cyclohexanone

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Re:a case of aldol condensation?
« Reply #2 on: September 08, 2004, 12:12:32 PM »
Aldol should be okay in this case.  If you were really worried about it you would use a base that would completely deprotonate the cyclohexanone so that it couldn't react with other cyclohexanone molecules (something like LDA).  However, it's probably not really necessary in this case because aldehydes are much more reactive than ketones.

Aldol reactions that give bad mixtures are the ones that try to react one aldehyde with another.  The only problem with the reaction at hand would be polymerization of the acetaldehyde.  That could probably be controlled by the order of addition.

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Re:a case of aldol condensation?
« Reply #3 on: September 08, 2004, 03:48:55 PM »
Aldehydes more reactive than ketones as carbonyl components? Sounds plausible. But I don’t know how you can explain this.

PS: So you can’t send an image to the forum?

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Re:a case of aldol condensation?
« Reply #4 on: September 08, 2004, 04:15:05 PM »
Carbonyl groups are electron defficient, right?  Alkyl groups are better electron donors than a hydrogen.  A ketone has two alkyl groups donating electron density by induction whereas an aldehyde only has one.  So an aldehyde carbonyl is more electron defficient than a ketone.  Furthermore, there is a small steric difference.  In this particular case the steric influence is more pronounced because the ketone is in a ring.

I have never tried attaching a picture file, so I don't know what the problem is.

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Re:a case of aldol condensation?
« Reply #5 on: September 08, 2004, 05:59:42 PM »
Right, I see, thanks...

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