ISSUE:

Good afternoon, I had an exercise on my agenda, which asked me for the product obtained by making the reaction of:

benzene + cyclohexene in catalytic amounts of sulfuric.

The result is a polyalkylation, since the cyclohexyl radical activates the molecule more.

Then the doubt assails me as to how I could obtain only the cyclohexybenzene .

First I had thought of an acylation with cyclohexanecarbonyl chloride and a subsequent reduction, but the product obtained would not be the one sought, since it is linked by a carbon in the middle.

I don't know if I have drawn the reaction sequence correctly either, but I think it would be something like this. How would you get cyclohexylbenzene without polyalkylations?

All the best!! and thank you!

I have been giving it some thought and I have thought of another way, but I do not know if it would be good in general terms.

1st reaction of benzene with cyclohexanone in an acid medium, to obtain a 3rd alcohol
2nd, distillation of the
3rd alcohol, dehydration of the
4th alcohol hydrogenation.

I don't know if in the dehydration stage of the cyclohexanol radical, the aqueous sulfuric acid can also react with benzene and then give other products.

Here the matter is complicated for me because until now I had seen the reactions with a single reaction center. Perhaps it is not too much of a problem that sulfonic groups get in since it is reversible and perhaps a desulfonation of the aromatic ring could be done at the end, but come on, I am only speculating.

all the best!

Hellooo!
To put a cyclohexyl as a substitute for benzene we should rent it. Acylation is not viable as there is no primary carbon that joins the aromatic ring. As you well say, alkylation has a moderate yield due to polyalkylations and attacking a ketone could solve it, although it inevitably introduces subsequent reduction stages.
Benzene is a lazy nucleophile, although it can attack cyclohexanone in an acidic medium, but you can also halogenate it, form an organometallic, and so you get a much more powerful nucleophile.

I send you a greeting!!!

ooh! Yes, thank you very much, I like the idea of ​​halogenating it to form the organometallic and attack cyclohexanone, thank you very much! <3