Base-Promoted Annulative Difluoromethylenation of Enaminones with BrCF<sub>2</sub>CO<sub>2</sub>Et toward 2,2-Difluorinated 2,3-Dihydrofurans
Jinbiao Ying, Ting Liu, Yunyun Liu, Jie‐Ping Wan
Abstract
A practical method for the synthesis of 2,2-difluorinated 2,3-dihydrofurans has been established via the [4 + 1] annulation of enaminones and BrCF2CO2Et with Na2CO3 promotion. This new protocol does not employ any transition metal reagent and enables the annulative difluoromethylation by the partial cleavage of the C═C double bond. In addition, the further treatment with hydrochloric acid in one pot leads to β-keto enoic acids (4-oxo-2-butenoic acids) via a formal enaminone C–N carboxylation.
Topics & Concepts
ChemistryAnnulationReagentCarboxylationTriple bondMedicinal chemistryCombinatorial chemistryCleavage (geology)Transition metalBase (topology)Double bondStereochemistryOrganic chemistryCatalysisMathematicsEngineeringMathematical analysisFracture (geology)Geotechnical engineeringFluorine in Organic ChemistryCyclopropane Reaction MechanismsSynthesis and Characterization of Pyrroles