Benzene attached to a cyclohexane EAS reactions

[510586]

What would the hexane act as if it is attacched to a benzene in EAS reations? like the benzene sharing 2 carbons with hexane. I assume donating because it's an R group?

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[NavyDDS1990]

alkyl groups on benzene acts as donating group. It will increase the reactivity

 

[510586]

So would it just direct anywhere? Since ortho in relation to one of the carbons of hexane is the meta of the other?

 

[BYU4you]

So would it just direct anywhere? Since ortho in relation to one of the carbons of hexane is the meta of the other?

It would direct ortho or para however you mentioned a benzene attached to two carbons of hexane. Do you mean like an attached cyclohexane? Or do you mean one hexane on C1 and one hexane on C2 kind of thing?

 

[510586]

It would direct ortho or para however you mentioned a benzene attached to two carbons of hexane. Do you mean like an attached cyclohexane? Or do you mean one hexane on C1 and one hexane on C2 kind of thing?

a hexane directly attached. Kind of like naphthalene but with a hexane instead. Idk the name of it

 

[FeralisExtremum]

You mean a fused ring?

Man that would be a crazy question, but I guess it would still direct ortho/para if possible. More likely para due to steric hindrance at the ortho positions.

 

[510586]

You mean a fused ring?

Man that would be a crazy question, but I guess it would still direct ortho/para if possible. More likely para due to steric hindrance at the ortho positions.

Yea and I think Dr. Romano says if there is only ortho and para to choose the para. Thanks!

 

[510586]

You mean a fused ring?

Man that would be a crazy question, but I guess it would still direct ortho/para if possible. More likely para due to steric hindrance at the ortho positions.

Actually in 288 of destroyer there is a naphthalene, and they add the electrophile ortho AND para. So I guess it's the same case and you have both products not just para.

 

[GBP12]

But in the case of that ring, which carbon do you use to get the ortho/para positions?

 

[510586]

It is symmetric so most likely either works

 

[GBP12]

It is symmetric so most likely either works

True.

 

[DAT Destroyer]

What would the hexane act as if it is attacched to a benzene in EAS reations? like the benzene sharing 2 carbons with hexane. I assume donating because it's an R group?

The hexane group attached to a benzene ring would be a hexyl group....a " big boy" indeed. It would act simply as an o/p director.....with like 99% para directing influence due to the size of it . Any alkyl group for that matter...would be an o/p activator.

Hope this helps.

Dr. Romano

 

[510586]

The hexane group attached to a benzene ring would be a hexyl group....a " big boy" indeed. It would act simply as an o/p director.....with like 99% para directing influence due to the size of it . Any alkyl group for that matter...would be an o/p activator.

Hope this helps.

Dr. Romano

In one one your examples using naphthalene you did both orth and para not just para. Even if it is 99% para do we stick with o/p?

 

[DAT Destroyer]

In one one your examples using naphthalene you did both orth and para not just para. Even if it is 99% para do we stick with o/p?

On the DAT they usually ask for the major product. The para is usually the major product.

 

[510586]

On the DAT they usually ask for the major product. The para is usually the major product.

So if they ask for major product and one has both or tho and para we still choose the one that has para alone? A lot of the destroyer questions the major was north or para as the answer such as the one I mentioned. Also in class they considered the major to be ortho or para not just para

 

[DAT Destroyer]

So if they ask for major product and one has both or tho and para we still choose the one that has para alone? A lot of the destroyer questions the major was north or para as the answer such as the one I mentioned. Also in class they considered the major to be ortho or para not just para

This really depends on the question.....For example.....If we brominate hexylbenzene.......we would get almost 100% para isomer......If we brominate propyl benzene,,,,,,,we get both ortho and para isomers,,,,,I would reckon that para would predominate by 75%.

Thus if the question asked for MAJOR product .....go with the para isomer,,,,,,If asked for all products,,,,,ortho and para would be considered.

Now.....If we had Toluene being brominated.....a methyl group is fairly small.....and we would get an almost even amount of ortho and para isomeric ratio !!!!!

Actually.....probably 55% ortho vs 45% para in this case,,,,,since there are 2 ortho positions vs 1 para position. Statistics wins out over Steric Hinderance....

Hopefully you see that usually para predominates,,,,,but not always. If the group is small....and methyl is relatively small......ortho predominates a small amount. If you check out the old ADA exams......You will see the questions are clear and straightforward.

Hope this helps.

Dr. Romano

 

[510586]

Thank yo

This really depends on the question.....For example.....If we brominate hexylbenzene.......we would get almost 100% para isomer......If we brominate propyl benzene,,,,,,,we get both ortho and para isomers,,,,,I would reckon that para would predominate by 75%.

Thus if the question asked for MAJOR product .....go with the para isomer,,,,,,If asked for all products,,,,,ortho and para would be considered.

Now.....If we had Toluene being brominated.....a methyl group is fairly small.....and we would get an almost even amount of ortho and para isomeric ratio !!!!!

Actually.....probably 55% ortho vs 45% para in this case,,,,,since there are 2 ortho positions vs 1 para position. Statistics wins out over Steric Hinderance....

Hopefully you see that usually para predominates,,,,,but not always. If the group is small....and methyl is relatively small......ortho predominates a small amount. If you check out the old ADA exams......You will see the questions are clear and straightforward.

Hope this helps.

Dr. Romano

Thank you so much for the detailed response. My teacher was pretty laid back and didn't really stress it that much so I was feeling unclear about it. Now I understand it much better.

 

[DAT Destroyer]

Thank yo


Thank you so much for the detailed response. My teacher was pretty laid back and didn't really stress it that much so I was feeling unclear about it. Now I understand it much better.

No worries,,,,,,I am anything but laid back.......I am excited even thinking about a BENZENE ring or an orbital !!!!!

 

[plusalpha]

You mean a fused ring?

Man that would be a crazy question, but I guess it would still direct ortho/para if possible. More likely para due to steric hindrance at the ortho positions.

how would the directing be affected if there's an ethyl group attached on the aromatic ring ortho to the cyclohexane ring..? A specific example of this case is OC question #10 in the 21 Destroyer. There are more than one alkyl groups attached adjacent to each other, so I'm not sure where the Br would go.