IN CASE OF TOLUENE the methyl group attached to the ring, increases the electron density at ortho and para positions by resonance without changing anything at the meta position. Thus the attacking reagent directly attacks at the electron rich site , thus the methyl group is ortho directing. you can easily understand the movement of electrons by following the direction of arrows in structures (I), (II) and (III). there is not any structure where the electrons can be seen on meta position.

resonating structures of toluene and explanation of electron density on various positions.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.