For monosubstituted benzenes especially those substituted with large groups (t-Bu, i-Pr), the para product will predominate in most EAS reactions. For example the bromination of t-butylbenzene would result in primarily the para product because of steric hinderance at the ortho site.
As you would expect in the reaction of 1,4-disubstituted benzenes the electrophile will attach at the least sterically hindered site.
With 1,3-dibsubstituted benzene its very unlikely (more difficult) to react between the two substituents as in the following example.
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