Which site would NaCN attacks (SN2)? Question



Attempt

I thought that the bromine atom farther from the ring would be substituted because of less hindrance, but the book says opposite, why?
The reaction proceeds by SN2, which is highly accelerated at the benzylic position, due to stabilisation of the transition state by conjugation with the aromatic ring.


  


So you'll have to replace the benzylic bromine.

References: Benzyl chloride: chemtube3d