question about explanation for today's DAT question of the day

[patricklin27]

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http://datquestionoftheday.com/orga...ail&utm_term=0_cd94ef0109-c6765f9cc0-43525285


the explanation mentioned that "para isomer would be the major product for steric considerations". However, I learned that the ortho isomer would actually be more stable (and hence the major product) because of dipole-dipole interactions. an ortho-electron withdrawing group would stabilize the electron donating group (in this case, ethyl group) right next to it. So, wouldn't the ortho isomer be the major product, not the para isomer since it is more stable? i thought steric interactions don't come into play unless there's two ED groups or two EW groups next to each other.

 

[bpester]

As far as I know, the ortho and para products should be relatively equal. I don't think a question would ask you which is the major product (because there are many other factors that come in to play) and have ortho and para as separate choices. Both the ortho and para positions are able to take advantage of the electron withdrawing groups inductive effect so both products should be formed in seemingly equal quantities. The ethyl group is not that large, but large enough to where steric factors may play a small role in hindering the ortho attack. I think it is important to note that the meta position would not be formed at all (or in extremely small quantities) due to the inability to utilize the inductive of the EWG.

 

[Ari Rezaei]

Every organic chem program has a slightly different way of teaching things. The main take away here is that the product would be ortho/para, but definitely not meta. That is what the DAT will test you on.

 

[Illfavor]

Yea, I think your concerns may be beyond the scope of this test 😀