Which of the following compounds will not undergo Friedel-Crafts reaction easily?
- Nitrobenzene
- Toluene
- Cumene
- Xylene
Answer
(1) Nitrobenzene
Solution
Friedel-Crafts alkylation/acylation is an electrophilic substitution and needs a ring that is not strongly deactivated.
In nitrobenzene, the -NO2 group strongly withdraws electrons (-I, -R) ⇒ the ring is strongly deactivated ⇒ Friedel-Crafts reaction does not take place easily.
Toluene, cumene and xylene carry electron-releasing alkyl groups (activated rings) ⇒ they react readily.
Answer: (1)