Hafnium (IV) bis(perfluorooctanesulfonyl)imide complex catalyzed synthesis of polyhydroquinoline derivatives via unsymmetrical Hantzsch reaction in fluorous medium

A facile and efficient synthesis of polyhydroquinoline derivatives was reported via four-component condensation reaction of aldehydes, dimedone, active methylene compounds, and ammonium acetate in the presence of Hf(NPf2)4 in C10F18 at 60 °C. The method offers several advantages including high yields, short reaction time, simple work-up procedure and catalyst reusability.

Graphical abstractThe synthesis of polyhydroquinoline derivatives via a four-component coupling reaction of aldehydes, dimedone, active methylene compounds, and ammonium acetate was successfully accomplished using metal bis(perfluorooctanesulfonyl)imide (M(NPf2)n, M = Sn, Hf, Yb, Sc, Y, Sm, La, Nd) as catalysts in fluorous solvent. Hafnium bis(perfluorooctanesulfonyl)imide catalyzed the high efficient preparation of polyhydroquinolines in fluorous solvent. Fluorous phase containing only catalyst can be reused several times.Figure optionsDownload full-size imageDownload as PowerPoint slide