S_NAr Mechanism: Nucleophilic Aromatic Substitution via Meisenheimer Complex

Learn SNAr (addition–elimination) on aromatic rings. Why you need an EWG (NO2) ortho/para to the leaving group, Meisenheimer intermediate, and product prediction.

  • Reaction: Ar–X + Nu− → Ar–Nu
  • What it does: Substitutes leaving group on aromatic ring under nucleophilic conditions
  • Typical reagents: Nu− (e.g., MeO−, NH2−) on nitro-activated aryl halides
  • Key intermediate: Meisenheimer complex (anionic sigma complex)
  • Driving force: Elimination of X− restores aromaticity
  • Exam type: Mechanism choice
  • Exam type: Predict product

Related Resources

All 194 Mechanisms — Aromatic & Organometallic (Advanced Orgo II) Mechanism Flashcards AI Reaction Predictor Ask the AI Tutor