Reactivity EDG & EWG

[SaintJude]

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Is it possible that EDGs increase reactivity for electrophilic aromatic substitution but also decrease reactivity for other reactions??

How are EDGs and EWGs related to reactivity?

 

[pfaction]

So aromatics are weak nucleophiles. Bases. Electron DONATING groups INCREASE that basicity. EWG decrease that basicity. If it's got a free lone pair, it's a EDG and increases reaction (exceptions: halogens). If it ain't got a free lone pair and can withdraw (C=O), its a EWG and reduces.

 

[syoung]

Is it possible that EDGs increase reactivity for electrophilic aromatic substitution but also decrease reactivity for other reactions??

How are EDGs and EWGs related to reactivity?

It also depends on where the EDGs/EWGs are located with respect to the reaction H+. (ortho, para, meta). If the cation is stabilized, the ortho/para substituents are favored. If not, then the meta is favored. If the EWG withdraws e- from the cation, then it is destabilized and meta will form. Like wise EDGs donates e- to the cation and will stabilize, thus increase reactivity at the ortho/para positions.

Like pfaction said, halides are EDG but deactivate, while OH, OR, alkyl groups NH2, NR2 donate in and help direct ortho/para.