[Maud]

I am having difficulties figuring out how to convert cyclohexanone into CYCLOHEXANECARBOXYLIC ACID; does anybody have an idea?

Thank you very much in advance!

[Maud]

Same kind of syntheses that I posted in the other thread ... same kind of trouble? Does anybody have an idea?

Thank you very much in advance!

[kriggy]

Hello, what reactions of producing carboxilic acids do you know? Can you use any of them in this case? You need to add one carbon to your molecule, what options do you know?
Try working backwards from your product to your starting material

PS: I know Im not a mod but you could have asked all your quetions in single thread 

[Maud]

Hello, what reactions of producing carboxilic acids do you know? Can you use any of them in this case? You need to add one carbon to your molecule, what options do you know?

PS: I know Im not a mod but you could have asked all your quetions in single thread 

Exactly... I need to add a carbon... so I was thinking about a Grignard reagent maybe? Because if use a condensation, how can I get the carbonyl "moved" to the following carbon? I'm confused...

[kriggy]

Than is indeed one option.
 How can you use grignard reagent to make carboxylic acid? What grignard reagent you need to make this cyclohexane carboxilic acid?

[Maud]

Than is indeed one option.
 How can you use grignard reagent to make carboxylic acid? What grignard reagent you need to make this cyclohexane carboxilic acid?

BrMgCOOH maybe but, careful... I have a cyclohexaNONE, not a cyclohexane... I can introduce the new carboxylic functionality but... how do I get rid of the ketone??? It makes me think if this is the appropriate strategy....

[kriggy]

Well your compound has pentavalent carbon so this is not the way. Also, grignard reagents are not stable in presence of acids so be careful.
Try to check this table, it might give you the idea.
http://upload.wikimedia.org/wikipedia/commons/5/53/Grignard_with_carbonyl.png

ps: Im aware that you have cyclohexanone

[Arkcon]

Maud:, I hope you don't mind my merging your two threads.  You may get an answer to one question that can help you with the other.  Right on.

[Maud]

Maud:, I hope you don't mind my merging your two threads.  You may get an answer to one question that can help you with the other.  Right on.

Sure, no problem. Thanks a lot!

[zapkinus]

am i understand correctly?

[kriggy]

No, we are talking about covnerting the cyclohexanone into cyclohexanoic acid. You are showing the reaction other way aroud.

[orgopete]

BrMgCOOH maybe but, careful... I have a cyclohexaNONE, not a cyclohexane... I can introduce the new carboxylic functionality but... how do I get rid of the ketone??? It makes me think if this is the appropriate strategy....

BrMgCOOH?, really?

I agree this is an often used example for using a Grignard. Hint, CO2 is the additional carbon.

[Maud]

BrMgCOOH maybe but, careful... I have a cyclohexaNONE, not a cyclohexane... I can introduce the new carboxylic functionality but... how do I get rid of the ketone??? It makes me think if this is the appropriate strategy....

BrMgCOOH?, really?

I agree this is an often used example for using a Grignard. Hint, CO2 is the additional carbon.

Mmm, I am really not sure about it... I would think about a condensation but... what about the ketone? Maybe I should do a reduction first....

[kriggy]

@Maud:
Sure thats the next logical step.
Please note that We are talking backwards: from your product to your starting material. Its called retrosynthetic analysis.
So now you know that you can make the  acid using grignard and CO₂. Then the next question is how to make the grignard from the ketone.

Usualy you dont know the starting material when designing synthesis but even if you do, its much easier to start with your product and that way: I can make the acid from grignard and CO₂. How are grignards made? How can I make the compound that is needed fo make the grignard? How do I make the compound that is needed to make the compound that is needed for synthesising grignard reagent? and so on until you hit the compound you can buy / or have in your lab.

It gives you better idea because usualy you have more than one options so while going from starting material to product gives you rather straightforward path, going backwards gives you more options in each step. I hope its not very confusing but its very important aspect of designing syntheses. Sadly I cant think of any good example to ilustrate this process, maybe tommorow 

[orgopete]

Mmm, I am really not sure about it... I would think about a condensation but... what about the ketone? Maybe I should do a reduction first....

There are many routes that a compound can be made and class assignments usually use them. However, we were not in the class to know. The acid could be synthesized via a condensation reaction, but not very easily. This question is frequently used with Grignard reactions. We could tell you exactly how it can be done and if you told us which textbook you were using, the page it could be found on. This will not help you on a test though.

Hint, if you had an alcohol, how could you make a bromide?

@kriggy
Re: retrosynthesis
I am old school. We learned how to do this before the term became popular. Now, this is my opinion about this. Students are virtually unable to think about possible reverse reactions unless they have first mastered the forward reactions.

The posters proposed Grignard could actually be a plausible step if applying retrosynthesis in a strict manner. It fails due to the implausible nature of the reagent. To that end, I virtually abandoned asking for starting materials until or unless I could no longer create a useful problem, e.g. Diels-Alder reactions. Think about it, does this post really show the poster is unaware of retrosynthesis or the reactions to complete it?