A copper-catalyzed multi-component reaction accessing fused imidazo-heterocycles via C-H functionalization

An efficient synthesis of fused imidazo-heterocycles is described using Cu(OTf)(2) in [bmim]BF4 by the multi-component reaction of pyridin-2(1H)-one or thiazol/benzo[d]thiazol-2(3H)-ones with O-tosylhydroxyl amine and acetophenones under microwave irradiation. The present method is very rapid and the product formation occurs via a C-H functionalization/tandem addition-cyclization process. The ionic liquid containing copper triflate is recovered and reused four times.