Electrochemical Trifluoromethylation/Cyclization of N′-Arylidene-N-acryloyltosylhydrazides for the Synthesis of CF3-Substituted Pyrazolones

Abstract

Herein, a mild and efficient synthesis of pyrazolones is disclosed through a sustainable electrochemical method. This electrolysis relied on cascade trifluoromethylation/cyclization by using CF₃SO₂Na as a trifluoromethyl source, which occurred directly at the anode. Two C–C bonds were formed to afford a series of novel trifluoromethyl-containing pyrazolone scaffolds without the addition of metals and redox reagents. Further mechanistic results showed that the reaction process may undergo a radical pathway.