Ytterbium perfluorooctanesulfonate as an efficient and recoverable catalyst for the synthesis of trisubstituted imidazoles

Synthesis of trisubstituted imidazoles was successfully accomplished using rare earth(III) perfluorooctanesulfonates (RE(OPf)3), RE = Sc, Y, La–Lu as catalysts in fluorous solvents. Ytterbium perfluorooctanesulfonates (Yb(OPf)3) catalyze the high efficient synthesis of trisubstituted imidazoles in fluorous solvents. By simple separation, fluorous phase containing only catalyst can be reused several times.