A versatile synthesis of substituted benzimidazolium salts by an amination/ring closure sequence

[GRAPHICS] A new method to produce benzimidazolium salts based on a successive Buchwald-Hartwig amination and ring closure is reported. A variety of different benzimidazolium salts can be prepared using this procedure. Amines that bear an alpha -chiral group undergo the reaction to furnish chiral benzimidazolium salts. The salts that lack a C2 substituent on the heterocycle are readily deprotonated to give nucleophilic carbenes.