Where would the E.A.S occur in this molecule?

[muhali3]

Where would an electrophilic aromatic substituion most likely occur in this molecule?

 

I assumed the ether is activating through resonance, and thus ortho/para directing. I am confused as to whether the methyl group or the ether is more activating, but I guessed that the EAS would occur at carbon A because that ring has more electron density than the other ring due to the methyl group (more stable carbocation). Is my logic correct or did I get this question wrong?

[mississippichem]

This is actually quite a tricky question. I believe "D" is the answer. "A" looks good at first site, but EAS occuring at "A" would result in the product being meta-substituted with reference to the methyl group. D works because it is para to the alkoxy activating group. I don't really know why,but activating groups tend to slightly perfer the para postion to the ortho. It must have something to do with steric hinderence in the kinetics. I've just noticed in literature that the para isomer tends to be perfered over the ortho when they compete.

[Horza2002]

I would also say D. While positions A, B and D are all activated by the oxygen lone pair, A and B are more sterically congested because they are ortho to the link to the second aromatic ring. Basically, the second ring would block the electrophile from approaching those positions therefore favouring D.