Deactivating or not?

[SGStudent]

The answer is +NR3 which I understand because it lacks a lone pair that can make the benzene more nucleophilic and therefore better reaction with electrophiles. But why isn't C with two oxygens attach consider electron withdrawing group? I thought since carbon is attach to more electronegative atom oxygen it becomes partially positive and so will make the benzene less nucleophilic.

If you can help me, I really appreciate it. Have a great holidays!

---

Members don't see this ad.

 

[datthirty]

I think like this:

you know -OH is active group, -OR also active group.
So, the two -OR acrive the C connect to it.

In one world, if you understand -OCH3 is better active group than -CH3, you will understand it.


Strongly Activating Groups[edit]

• -NH2
• -NHR
• -NR2
• -OH
• -O-

R = alkyl

Strongly activating substituents favor electrophilic substitution about the ortho and para positions.
This is illustrated by drawing the resonance structures of aniline: [1]

Moderately Activating Groups[edit]

• -NHCOCH3
• -NHCOR
• -OCH3
• -OR

Weakly Activating Groups[edit]

• -CH3
• -C2H5
• -R
• -C6H5

 

[datthirty]

If you still do not understand, just forget the weired group. I think the real test unlikely asks such knid of weired group.

 

[SGStudent]

Okay, thanks for the help.