Question

During the Hunsdiecker reaction, if the aromatic ring contains electron-donating group rather than the electron-withdrawing group then:

• A. the bromine will substitute one of the carbon on the aromatic ring rather than promoting the Hunsdiecker reaction.
• B. the bromine will add one of the hydrogen on the aromatic ring rather than promoting the Hunsdiecker reaction.
• C. the bromine will substitute one of the hydrogen on the aromatic ring rather than promoting the Hunsdiecker reaction.
• D. all of these

Answer 1

Answer: (C)

the bromine will substitute one of the hydrogen on the aromatic ring rather than promoting the Hunsdiecker reaction.

As we know Hunsdiecker reaction is free radical substitution if in carboxylate ion R is an aromatic ring and contains Electron donating group. The electron donating group release electron towards the ring and negative charge increases over the ring so a hydrogen atom is released which attracts the Bromine radical to replace Hydrogen. If the electron withdrawing group is present. Bromine atom attaches to the carboxylate group.