Benzyne Mechanism
( \newcommand{\kernel}{\mathrm{null}\,}\)
Two mechanisms have been proposed for nucleophilic aromatic substitution, one of which involves a benzyne as the intermediate and, therefore, is called benzyne mechanism.
eg:
mechanism:
Step 1:
Step 2:
Step 3:
Step 1 requires a very strong base. Thus, for the benzyne mechanism to be operant, the medium must be very strongly basic.
see also SNAr mechanism