# Regioselectivity in Friedel–Crafts acylation of thiophene

In the above reaction, I understand that $$\ce{AlCl3}$$ is acting as a Lewis acid to generate an acylium ion, which is a strong electrophile.

Would this electrophile attack at carbon 2 or 3?

I think it would attack at C-3, as the resulting positive charge at C-2 would be stabilized by resonance using the lone pair on sulfur.

• Apr 30, 2017 at 12:49