Answer to Question #115363 in Organic Chemistry for Ujjwal

Question

What do you understand by meta directing deactivators

Answer 1

The deactivating groups deactivate the ring by the inductive effect in the presence of an electronegative atom that withdraws the electrons away from the ring. We can see from the mechanism below that when there is an electron withdraw from the ring, that leaves the carbons at the ortho, para positions with a positive charge which is unfavorable for the electrophile, so the electrophile attacks the carbon at the meta positions.

The deactivating group directs the reaction to the meta position.

Examples of deactivating groups in the relative order from the most deactivating to the least deactivating:

-NO2, -CF3> -COR, -CN, -CO2R, -SO3H > Halogens