Synthesis of Fully Substituted Pyrazoles with a Dicyanomethyl Group via DBU/Lewis Acid-Mediated Annulation of D–A Cyclopropanes with Arylhydrazines

Abstract

The efficient synthesis of fully substituted pyrazoles with a dicyanomethyl group was developed via an annulation reaction of 2-aroyl D–A cyclopropanes with arylhydrazines in the presence of DBU/AlCl3 reaction systems. This synthetic approach featured a wide range of readily available aroyl-substituted D–A cyclopropanes with diverse functional groups and a diversity of substituents on pyrazole products and had operationally simple and mild reaction conditions.