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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: bmorvan on June 15, 2011, 06:21:55 AM

Title: Dehydrohalogenation of alpha-chloro acid
Post by: bmorvan on June 15, 2011, 06:21:55 AM

Dear,
I try to dehalogenate an alpha-chloro acid with KOH/H2O in order to make an acrylic analog but the product is unchanged.
Have you an idea?
Thank a lot
BM

Title: Re: Dehydrohalogenation of alpha-chloro acid
Post by: asa029 on June 17, 2011, 04:04:50 AM

So you are trying to eliminate? Can you make the bromo or iodo derivate instead of the chloro? Leaving group effects are important. You can also try another base, preferably one that is a lousy nuchleophile so you don't risk substitution in competition with eliminatio, potassium tert-butoxide comes to mind. What temperature are you running the reaction at? Higher temperatures favorise eliminations. The nature of the solvent can be important too!

Good luck!

Title: Re: Dehydrohalogenation of alpha-chloro acid
Post by: fledarmus on June 17, 2011, 08:52:23 AM

Quote from: asa029 on June 17, 2011, 04:04:50 AM

So you are trying to eliminate? Can you make the bromo or iodo derivate instead of the chloro? Leaving group effects are important.

<snip>

Good luck!

Agreed - most of the reactions of this sort that I've seen use at least a small amount of KI in the reaction to generate the iodo derivative in situ