Synthesis of Difluoromethylated Pyrazoles by the [3 + 2] Cycloaddition Reaction of Difluoroacetohydrazonoyl Bromides
Tongyu Han, Ke‐Hu Wang, Ming Yang, Pengfei Zhao, Feng Wang, Junjiao Wang, Danfeng Huang, Yulai Hu
Abstract
As novel and efficient difluoromethyl building blocks, difluoroacetohydrazonoyl bromides have been synthesized for the first time. The synthetic utility of this reagent for the construction of difluoromethyl organic compounds is demonstrated by their effective regioselective [3 + 2] cycloaddition reactions with ynones, alkynoates, and ynamides. The reactions provide a novel and efficient protocol to access difluoromethyl-substituted pyrazoles in good to excellent yields.
Topics & Concepts
CycloadditionReagentRegioselectivityChemistryCombinatorial chemistryReaction conditionsOrganic chemistryMedicinal chemistryCatalysisFluorine in Organic ChemistrySynthesis and Reactions of Organic CompoundsCyclopropane Reaction Mechanisms