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I'm trying to grasp the Birch reduction. In the lecture about it, it's said that the EWG group stabilizes ipso and para position through resonance. I tried to understand that by drawing resonances without success. What is wrong in it?

resonance structures

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  • $\begingroup$ You seem to have an extra dot (electron) in the first structure, which is muching things up all over the place. What is going on there? $\endgroup$ – Lighthart Mar 28 '16 at 5:40
  • $\begingroup$ sorry;; that extra electron is from Na $\endgroup$ – NK Yu Mar 28 '16 at 6:12
  • $\begingroup$ So this is sodium donating an electron to an aromatic compound with an electron withdrawing group? $\endgroup$ – Lighthart Mar 28 '16 at 15:22
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TL;DR: This question may not be readily answered with Lewis structures.

The problem is the electron is delocalized into an antibonding orbital. By analogy, we can examine this concept with molecular oxygen. The Lewis structure for molecular oxygen:

Lewis structure for oxygen

This clearly is a double bond, with all spins paired. Now observe the molecular orbital diagram below:

MO diagram oxygen

The top energy levels clearly show oxygen with two unpaired electrons, which contradicts the Lewis structure completely. There is no real way to simultaneously convey these two situations.

Similar diagrams exist and may be used for the aromatic system with an electron-withdrawing group exist, but they are rather complicated.

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