SN1/SN2 Reactions Question

[klutzy1987]

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I saw an interseting question and i was wondering if i was right.

The question read, Why doesn't HI work to cleave diphenyl ether???

I think the answer is because the reaction between a strong acid and a ether is an SN2 or SN1 reaction and those dont work by phenyl or aryl. Is that true and would that be the correct answer

 

[smile101]

So...basically this is a cleavage rxn and phenyl is a very bad leaving group, so you won't be able to kick off one of the phenyl. I think your answer is right except for the strong acid part...what were the exact answer choices?

 

[klutzy1987]

It was from a textbook not a DAT review book and the book didnt have multiple choice. But Phenyl wouldnt be a leaving group anyways because the halide would attack and it would split in a phenoxy group and a phenlyhalide. The phenoxy though is not stable and i do no think it would be a good leaving group.

 

[scuzfly]

Part of it would be steric hindrince. You have to bend two phenyl groups (bulky) for the HI to attack. You also have the repulsion of the electrons pushing against the phenyls much like H2O.

IF the HI was able to react you would probably have a phenOL as a result because the ether would turn into an alcohol if the OTHER phenyl left with the Iodine. This changes from secondary to primary stability which would favor SN2 (i believe) attack from the displaced phenyl.


Someone correct me if my thinking is wrong.