A One-step Synthesis Of Gem-difluoroolefins From Alcohols

Objective:As fluorine element possesses many special properties,such as high electronegativity,small atomic radius,and low polarizability,the incorporation of fluorine atoms into organic molecules may significantly change their physicochemical properties.Furthermore,gem-difluoroolefins have been widely used as versatile intermediates for the preparations of fluorinated compounds.The development of efficient protocols for the synthesis of gem-difluoroolefins has received increasing attention.Therefore,we hope to achieve the effective synthesis of the Difluoroalkenes by a mild and efficient method.Methods:This paper uses PDFA as the phosphorous ylide reagent to synthesize gem-difluoroalkenes from alcohols in one step.In this reaction,the alcohol is oxidized with Burgess reagent to generate aldehyde and then converted to geminal difluoroalkene by Wittig reaction.Result:In this paper,a series of Difluoroalkenes were successfully synthesized in nitrogen atmosphere by the above methods.Conclusion:The difluoro-alkylation of alcohols with stable and storable Ph₃P⁺CF₂COO^-（PDFA）as ylide reagent has been carried out.The method has the advantages of good compatibility of functional groups and substrate,simple and convenient operation,mild reaction system,easy access to raw materials,safe reagent and high reaction efficiency.