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Topic: Iodoform reaction  (Read 4240 times)

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Offline Necrophobos

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Iodoform reaction
« on: March 13, 2011, 02:18:43 PM »
Hello, I have a doubt regarding the iodoform reaction and am hoping someone would be able to clarify it for me.

Why is this reaction a typical reaction of methyl ketones?

Thanks in advance ;)

Offline stewie griffin

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Re: Iodoform reaction
« Reply #1 on: March 13, 2011, 02:26:13 PM »
You question is a bit nebulous. The iodoform reaction is specific to methyl ketones, so I'm not sure how one could answer why the iodoform reaction is a typical reaction of methyl ketones.
Perhaps you meant to ask why methyl ketones are able to undergo the iodoform reaction? If so, consider ability to enolize, and also the electrophilicity of a ketone bearing a trihalomethyl group.

Offline Necrophobos

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Re: Iodoform reaction
« Reply #2 on: March 13, 2011, 03:00:22 PM »
Well I'm new to organic chemistry so I really don't know about the ability to enolize and electrophilicity :/

What I meant though was why do methyl ketones react in the iodoform reaction and, for example, diethyl ketone doesn't. But I've read some things meanwhile and am guessing it's because of the formation of a carbonyl group, that reacts with a base, later forming the carboxyl group.

Offline zolarpwr

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Re: Iodoform reaction
« Reply #3 on: March 14, 2011, 07:42:01 PM »
You're asking the right question. That's the key to understanding.

Now ask yourself what would form from diethyl ketone under those conditions (iodine and base). Compare its electrophilicity with what you would get with the methyl ketone, before hydrolysis. What would the carbon group in place of the extra halogen do?

Offline adianadiadi

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Re: Iodoform reaction
« Reply #4 on: March 19, 2011, 03:45:55 AM »
Iodoform, CHI3 is only formed when there are alpha methyl groups i.e., adjacent to the carbonyl carbon. There must be three hydrogens to be replaced by iodine atoms. Otherwise no iodoform is going to be formed.


Offline Necrophobos

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Re: Iodoform reaction
« Reply #5 on: March 21, 2011, 02:16:36 PM »
Thanks everyone, I think I understood it ;)

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