Simultaneous Denitrative C–C Bond Formation and Construction of Pyrazole Ring Leading to 1,1'-Diphenyl-4,4'-bipyrazole

– b -Formyl- b -nitroenamine reacts with phenylhydrazine to afford 1,1'-diphenyl-4,4'-bipyrazole. The unusual C–C bond formation was found to proceed in an ionic mechanism initiated by excess amount of hydrazine. This reaction is interesting from a viewpoint of synthetic chemistry because it simultaneously involves the construction of a pyrazole ring and the formation of a C–C bond under neutral conditions. b -Formyl- b -nitroenamine ( 1 ) possesses multiple functionalities such as a , b -unsaturated aldehyde, nitroalkene, and enamine. The push–pull property generates a highly electron-biased C–C double bond, which reacts with either nucleophiles or electrophiles to afford versatile heterocyclic frameworks (Scheme