A Traceless Heterocyclic Amine Mediator in Regioselectivity−Switchable Formal [1 + 2 + 2] Cycloaddition Reaction to 1,3,4- and 1,4,5-Trisubstituted Pyrazoles
Jie Huo, Xiao Geng, Wanmei Li, Pengfei Zhang, Lei Wang
Abstract
Switchable multicomponent reactions have been attractive tools for the construction of compound libraries with skeleton diversity and complexity by slightly changing the reaction conditions. Described herein is a regioselectivity-switchable formal [1 + 2 + 2] cycloaddition reaction from difluoroalkyl compounds, enaminones, and RNHNH 2, ultimately using 1-methylindazol-3-amine as a traceless mediator to switch the inherent regioselectivity of 1,3,4-trisubstituted pyrazole formation to 1,4,5-trisubstituted pyrazoles. Remarkable features of this work include mild conditions, simple operation, and broad scopes.
Topics & Concepts
RegioselectivityChemistryCycloadditionAmine gas treatingCombinatorial chemistryPyrazoleMoleculeReaction conditionsOrganic chemistryCatalysisClick Chemistry and ApplicationsChemical Synthesis and AnalysisMulticomponent Synthesis of Heterocycles