The 3-substituted indoles add the electrophile to position 3, rearranging it to position 2 at a later stage.

indole 07 electrophile substitution

The reaction product can be formed by a mixture of two compounds, resulting from the rearrangement of the electrophile and the substituent.

indole 08 electrophile substitution

No thoughts on “Electrophilic substitution with position 3 of the indole occupied”