activater: ortho vs para?

[joonkimdds]

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According to destroyer #15, aromatic-NH-Carbonyl-aromatic
structure prefers para position over ortho.

How do we know which position it prefers between para and ortho?
there are two ortho positions and 1 para positions available so shouldn't ortho be the major product?

 

[sunshine222]

Probably steric hindrance... bulky side groups like aromatics will tend to go para.

 

[gentile1225]

definitely steric hinderance. a substituent will rarely be directed ortho if the director is bulky such as an aromatic hydrocarbon like a benzene ring.

 

[keliao]

i agree with the above.

 

[heatwheat]

Steric hindrance makes that para position easier to get to than the ortho position.