Expeditious and Efficient Synthesis of Benzoxazoles, Benzothiazoles, Benzimidazoles Catalyzed by Ga(OTf)3 under Solvent-Free Conditions

A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga(OTf)(3) under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.