Reaction mechanism of substitution reaction

Question

Can someone please let me know the reaction mechanism for the reaction of benzyl chloride with thiourea ? please explain with the reaction diagram and electron movement.

Answer 1

Sulfur attacks the benzylic carbon from the back side with a cone angle that varies from 180 to 160 degrees. 

 

It is a bimolecular substitution (synchronous or single-step displacement). As such it has a single transition state and is facile because the transition state of the electrophilic carbon is exceptionally charged being benzylic and stabilized by resonance delocalization. The reaction is exothermic if you plot H vs reaction progress. The new bond is stronger than the former C-X bond.

 

An arrow is drawn from a lone pair on sulfur to the benzylic carbon and then the bond to chlorine is broken by drawing an arrow from the center of the bond to the chlorine atom. This is how to depict the S-C bond formation and C-Cl bond rupture.