Cine-Substitutions at Five-Membered Hetarenes Enabled by Sulfonium Salts.

We report a nucleophilic substitution reaction of five-membered hetarylsulfonium salts that results in a change of the substitution pattern on the arene. The products of these cine-substitutions are hard to access synthetically otherwise. The sulfonium salts that serve as starting materials are generated by a highly site-selective C-H functionalization reaction.