[sammy_0559]

My Question is about formed Enol and why it doesn't undergo multiple Halogenations. I wrote it out worked the mechanism understood it best I could.

What I understand as of now.
-Tautomerization is what produces the enol from the ketone or aldehyde.
-Because the product is less reactive it is harder to form the enol. NOT the case in base promoted Alpha halogenation.
-It is more stable in the keto form.
-When the enol forms it Reacts.
-conjugation of the ketone may play a role in driving it to produce more enol than usual.
Please correct me if i have any misconceptions.

But anyways. i read the text book and could not find my answer.

My professor asked me Why under Acidic conditions doe it not form the Enol after it has reacted and formed a product?
Vs In base promoted You can add OH and it will pluck off a hydrogen and add a halogen until it becomes an haloform.

So why doesn't the enol form from the product of an acid cat. halogenation?

I asked my professor and he will not answer my question, until i figure it out. Then He will confirm.
Thank you!

Sammy.

[billnotgatez]

I think you should read the forum rules because we tend to give hints and not answers
Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.

[sammy_0559]

I think you should read the forum rules because we tend to give hints and not answers
Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.

I apologize for not reading first, I'm familiar with forums but first Science forum i join. It is not an assigned question. Rather a question that I took note of in class and he left the rest of the class to ponder.

Our course consists of 4 exams @ 25% each. I can post an image on everything i have thought of but I'm completely down to discuss it. Just did not want to over kill with typing.

 Any hints would be appreciated because all i got from my professor him restating the question. He told me i was over thinking it and it was a lot simpler that it appears to be.
It just bugs me (don't want to move on until i fully understand it), I'm working all the practice problems as we speak in the back of the book hopefully to gain enough knowledge to answer it.

[orgopete]

-Tautomerization is what produces the enol from the ketone or aldehyde.
-Because the product is less reactive it is harder to form the enol. NOT the case in base promoted Alpha halogenation.
-It is more stable in the keto form.
-When the enol forms it Reacts.

It is correct that as the enol forms, it reacts (just like an alkene). What does that tell you abou the assumption about the tautomerization (being assumed)? Hint, an acid catalyst is required to initiate the reaction. If the rate limiting step were enol formation, which ketone would you predict to be more basic, the halogenated or the unhalogenated ketone?

[sammy_0559]

-Tautomerization is what produces the enol from the ketone or aldehyde.
-Because the product is less reactive it is harder to form the enol. NOT the case in base promoted Alpha halogenation.
-It is more stable in the keto form.
-When the enol forms it Reacts.

It is correct that as the enol forms, it reacts (just like an alkene). What does that tell you abou the assumption about the tautomerization (being assumed)? Hint, an acid catalyst is required to initiate the reaction. If the rate limiting step were enol formation, which ketone would you predict to be more basic, the halogenated or the unhalogenated ketone?

Brilliant!! I think I get it now, we learned previously that halogens decrease the basisity of the carbonyl oxygen making the overall halogenated ketone more acidic.  So the unhaloed ketone is more basic. I understand that equilibrium shifts in favor of the products drastically.

 So because of the inductive effect of the halogen it basically draws the line for any more enols to form.

Am I on track or half asleep? Lol

[orgopete]

You are on the beam as long as you know that enol formation occurs from the protonated ketone. I would expect loss of a proton from the oxygen to still be predominant. Loss of a proton from carbon will be minor, but lead to an enol.