A New Life for an Old Reagent: Fluoroalkyl Amino Reagents as Efficient Tools for the Synthesis of Diversely Fluorinated Pyrazoles

Abstract Herein we describe the first practical method for the regioselective preparation of 3,5-bis(fluoroalkyl)pyrazoles. Starting from commercially available fluoroacetoacetates and by using (tetrafluoroethyl)dimethylamine as a convenient CF2H transfer reagent, this straightforward one-pot sequence affords highly substituted pyrazoles in good yields and excellent regioselectivity. Furthermore, these carboxylate intermediates were converted into the corresponding pyrazolic acids, which are valuable building blocks for the design of novel bioactive ingredients.