[orange]

Hi all
What is effect of withdrawing groups of alkylhalides on friedel craft reaction?  will the Cl-CH2-CCl3 undergo the FC reaction with toluene?

Thanks

[AromaticAcrobatic]

Yes, ethyl Chloride will undergo the Fc alkylation with toluene. Remember alkyl groups are weakly activating because of hyperconjugation, but be careful because if the toluene had halogens on it instead of H then it would be strongly deactivating.

 

[AromaticAcrobatic]

Yup, so sorry about that I just realized I misread your question.
The 2,1,1,1-tetrachloroethane should undergo Fc alkylation via CH2 carbocation.

 

[orange]

Yup, so sorry about that I just realized I misread your question.
The 2,1,1,1-tetrachloroethane should undergo Fc alkylation via CH2 carbocation.

 

Thank you. Will carbocation form? because there is a strong withdrawing effect.

[orgopete]

I'm not sure what this question is about. Toluene will react. The question is what will be the product? The starting material will probably be the least reactive reagent. The product(s) will increase in reactivity. What I don't know is which chlorine will react first and further rearrangements? Will the product be 1,1,2,2- or 1,1,1,2-tetratolylethane?

[AromaticAcrobatic]

I'm thinking the carbocation will form and the chlorine on the CH2 will be the first chlorine to react. My reasoning behind this is, if we think mechanistically a carbocation is more stable(lower in energy) on the CH2 then if a carbocation was placed on a carbon that already is partially +. While the CH2 might have some partial + character because of the trichlorinated Carbon a + charge on the CH2 would still be lower in energy then if a carbocation was to form on a carbon that already is partially +.
But like Orgo was getting at, it might take alittle bit or some heat.
It seems like rearrangments would be unlikely though, because it takes more energy to use one of the trisubstituted chlorines and then rearrange with a hydrogen leaving a carbocation on a partially + carbon then it would be to just use the CH2 Chlorine..

 

[AromaticAcrobatic]

I'm not sure if that first part is clear. I realize both carbons have some partial + character to start, although the trisubsitituted Carbon has more partial + character. So it seems like Carbon in all of its infinite wisdom will trade the partial + charge for a full blown + charge next to an area of high electron density(Toluene) knowing that the longest part of the reaction has already happened and its essentially trading a partial + charge for being neutral as well as a bond next to an area of high electron density, which would be lower in energy then bonded to chlorine.
The alternative would be using the trisubsitituted Carbon, which after the reaction would still have a partial + charge only now it's withdrawing electron density from toluene increasing the disorder. Even if there was a rearrangement the benzylic Carbon would still be partially + which would increase the disorder of the environment. So, what is more likely? A reaction which increases or decreases the disorder of it's environment?