Acetic acid-catalyzed (3 + 2) cyclization
reaction of
substituted
2-aroyl-3-aryl-1,1-dicyanocyclopropanes with arylhydrazines was investigated
for the efficient synthesis of 4-dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles
in good yields, in which 4,5-double substituents are predominantly trans selective. This approach included the consecutive
condensation, ring opening, and double nucleophilic cyclization reaction.