Access to 1-Aryl-pyrazolin-5-ones via Photocatalytic Chemoselective Tri/Difluoromethylation and Cyclization of <i>N</i>-Methacryloyl Aldehyde Hydrazones
Changduo Pan, Yanmei Gong, Miao Zeng
Abstract
A photocatalytic trifluoromethylation and 5 -endo-trig cyclization of ( E )- N ′-arylidene- N -phenylmethacrylohydrazides was developed for the construction of trifluoromethylated pyrazolin-5-one derivatives using easily available trifluoromethyl thianthrenium triflate (TT-CF 3 + OTf – ) as the trifluoromethyl source. This protocol exhibits a broad substrate scope and excellent chemoselectivity. The utility of the current strategy is further highlighted by its application in the late-stage modification of drug molecules. Furthermore, difluoromethylative cyclization was realized using PhI(O 2 CCHF 2 ) 2 under similar conditions.
Topics & Concepts
ChemoselectivityTrifluoromethanesulfonateChemistryTrifluoromethylationAldehydeTrifluoromethylPhotocatalysisSubstrate (aquarium)ArylCombinatorial chemistryCatalysisMoleculeOrganic chemistryMedicinal chemistryGeologyOceanographyAlkylFluorine in Organic ChemistrySynthesis and Reactions of Organic CompoundsCyclopropane Reaction Mechanisms