[psychkub]

The trick is to use the correct reactants in order and give the corresponding letters that would eventually yield the target molecule. You can only use what is given.



I tried doing this using the lithium cyclohexane and making it into a dialkyl cuprate but I get stuck after the addition of the ethyl group (D,G,F....?) so I figured this way was wrong (I think).

I then tried the grignard way (in our class, the professor said to assume the R-Li reacts the same way as R-MgBr for purposes of simplicity) and got up to D,B,J,C,I to give acetophenone... can you just neutralize again to get the target? Is this even remotely correct?

The above is of utmost concern, but if you have time, can anyone corroborate this one:



and I get FEHGBD.

[Squirmy]

D,B,J,C,I to give acetophenone

you might look up the structure of acetophenone, but there's bigger fish to fry

I know it's not your fault that the question is given in letters, but it would be easier to catch mistakes/see your line of thinking if you could draw out your intermediates.

There is a problem with your synthesis...looks like you're trying to use CH3I as a Grignard reagent, but it's not.

Check the first step....if you could take your pick of carbonyl compounds to use in the addition reaction with cyclohexyl lithium, what would it be?

[psychkub]

D,B,J,C,I to give acetophenone

you might look up the structure of acetophenone, but there's bigger fish to fry

Oh gawd, you're right. It's not a benzene ring... nevermind on that.

Here's the work I made for both problems:

Check the first step....if you could take your pick of carbonyl compounds to use in the addition reaction with cyclohexyl lithium, what would it be?

I'd ultimately want acetaldehyde to begin with but I don't have anything that could add a methyl group to the formaldehyde... at least not that I'm aware of, since we have not gone over carbonyl reactions in class yet.

[Squirmy]

All around great job! The route at the top is a bit of a dead end with the reagents you have available. However, it would be a good exercise to finish it off with whatever reagents it takes.

The route in the middle has the previously mentioned problem that CH3I is not a Grignard reagent. You could make a Grignard reagent from it, but you don't have magnesium as one of your reagents. (I personally don't like this format of question...seems like it stymies creativity.)

You're right...acetaldehyde is what you would want for the alkyl lithium addition. Considering all of your reagents, not just formaldehyde, is there any way you could make acetaldehyde?

[Squirmy]

For the second problem...you're very close. The product of the last step is missing something that you'll have to get rid of to get the desired product.

[psychkub]

All around great job! The route at the top is a bit of a dead end with the reagents you have available. However, it would be a good exercise to finish it off with whatever reagents it takes.

The route in the middle has the previously mentioned problem that CH3I is not a Grignard reagent. You could make a Grignard reagent from it, but you don't have magnesium as one of your reagents. (I personally don't like this format of question...seems like it stymies creativity.)

You're right...acetaldehyde is what you would want for the alkyl lithium addition. Considering all of your reagents, not just formaldehyde, is there any way you could make acetaldehyde?

OMG so, take ethanol and react it with PCC will give me acetaldehyde and I can just take that and react it with the cyclohexyl lithium and neutralize the enol to get the target. Thanks SOOOO much for clarifying that. I was so immersed in trying to work it out the other way that I wasn't paying attention and it was right in front of my face.

Question regarding #2 (121) Are you saying there is an additional step that I'm missing after the H⁺/Heat part?

If I understand what you're talking about, the reaction with the acid will add an H giving OH.... if it reacts with another proton it will give me an oxonium ion which can function as a leaving group leaving me with the isopropyl cyclohexane... or is that not correct?

[Squirmy]

What kind of product do you get from dehydration of an alcohol?

[psychkub]

What kind of product do you get from dehydration of an alcohol?

Oh! the dehydration of the alcohol give me an alkene.... using the H2/Pt will give me the alkane I seek.

I believe that's right....

You've been very helpful! I thank you!!!!!

[psychkub]

[Squirmy]

You're welcome! good luck