Benzyne Mechanism: Elimination–Addition Nucleophilic Aromatic Substitution

Learn the benzyne (elimination–addition) mechanism: strong base forms benzyne, nucleophile adds, and why you often get regioisomer mixtures.

• Reaction: Aryl halide + strong base → substituted arene
• What it does: Substitutes X on aromatic ring under harsh basic conditions
• Typical reagents: NaNH2, liquid NH3; aryl halide with ortho H
• Key intermediate: Benzyne
• Driving force: Relief of strain / restore aromaticity after addition
• Exam type: Mechanism choice
• Exam type: Predict product