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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: ClarkS on June 15, 2022, 11:51:11 AM

Title: What are the correct products of this reaction?
Post by: ClarkS on June 15, 2022, 11:51:11 AM
Hey guys! Would you mind helping me with solving this easy reaction? I solved this at first pretty quickly, my original answer is shown under the number 1, but then when I was checking whether Im correct with the app OrgoSolver, it showed me different result (number 2). My thought process was that both groups react into ortho and para positions, but it would prioritise ortho and para positions of the CH3 group as it is activating group while Br is deactivating group. OrgoSolver tho thinks differently as you can see. Thank you in advance!
Title: Re: What are the correct products of this reaction?
Post by: Babcock_Hall on June 15, 2022, 12:40:56 PM
It's been a while since I have thought about aromatic substitutions, but I like to think of activating/deactivating and o,p-directing/meta-directing as two different qualities entirely.
Title: Re: What are the correct products of this reaction?
Post by: hollytara on June 18, 2022, 02:10:55 AM
So CH3 is activating and o,p directing by an inductive effect.

Br is deactivating (inductive) but o,p directing by a resonance effect.

We generally think that when two directing influences are in conflict, the more activating group "wins" the directing struggle.  Here, both Br and -CH3 are o,p; but since they are ortho, they direct to different locations.  CH3 is more activating - but Br is directing by the stronger effect, resonance.  So this is a very subtle case. 

In reality, I wouldn't be surprised to see a significant mixture of the two types of products. 

Title: Re: What are the correct products of this reaction?
Post by: wildfyr on June 19, 2022, 02:53:35 PM
I would consider this a borderline trick question, as the reality would almost certainly be a mishmash of all the products.
Title: Re: What are the correct products of this reaction?
Post by: rolnor on June 19, 2022, 02:59:29 PM
Even tribromo probably to some extent.
Title: Re: What are the correct products of this reaction?
Post by: Meter on June 20, 2022, 11:32:59 AM
There is a hierarchy to the extent functional groups are ortho-para og meta directing and activating/deactivating. For these kinds of problems, the teacher most likely wants you to use this to theoretically predict the major product.