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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: mirracle4 on April 26, 2015, 12:53:02 AM

Title: Please help with mechanism (base-catalyzed isomerization of aldol)
Post by: mirracle4 on April 26, 2015, 12:53:02 AM

I have to draw a mechanism for this "base-catalyzed isomerization" but I cannot figure out how to start. I don't think the carbon that the hydroxyl group is attached to gets deprotonated since a hydroxyl group is electron donating. I also don't think the alcohol gets deprotonated by the hydroxyl ion. Can someone please help me out with this one?

https://www.flickr.com/photos/130590666@N04/17084595908

Title: Re: Please help with mechanism (base-catalyzed isomerization of aldol)
Post by: orgopete on April 26, 2015, 02:18:25 AM

Hint: a carbonyl group is electron withdrawing and can increase the acidity of alpha hydrogens.

Title: Re: Please help with mechanism (base-catalyzed isomerization of aldol)
Post by: pgk on April 26, 2015, 06:29:02 AM

Try to draw the mechanism of the inverse reaction and then, get back. It might be helpful.
Which reaction is more favorable (more stable product) and why?

Title: Re: Please help with mechanism (base-catalyzed isomerization of aldol)
Post by: mirracle4 on April 26, 2015, 06:08:13 PM

Ok I think I got it... And I know that the reaction as written forms the more stable product, but is this because the pi bond is more substituted in this product? Is that the only reason?

Title: Re: Please help with mechanism (base-catalyzed isomerization of aldol)
Post by: pgk on April 27, 2015, 11:06:26 AM

Which one is more conjugated and why?