Determinative role of ring size and substituents in highly selective synthesis of functionalized bicyclic guanidine and tetra substituted thiophene derivatives based on salt adducts afforded by cyclic thioureas and ketene dithioacetal

For the first time in the history of synthesis of thiophene and bicyclic guanidine frameworks, a protocol has been invented performing under simultaneous presence of free-catalyst and free-base at room temperature.