Study On The Addition Reaction Of Ethyl Bromide Difluoroacetate With C=O And C=N Bond

Organic compounds containing difluoromethyleneunit have unique physical and chemical properties and biological activities,and they have been widely used in the fields of medicine,pesticides and materials science.There are two main methods for synthesizing difluoromethylene-containing compounds: one is direct fluorination,which directly introduces difluoromethylene group into non-fluorinated organic compounds by electrophilic or nucleophilic fluorinating reagents;the other is a difluoromethylene-containing building blockfluorination,which constructs difluoromethylene-containing organic compounds from difluoromethylene-containing raw materials through functional group conversion and carbon-carbon bond formation.Difluoromethylene-containing building blocks are inexpensive,stable and commercially available.This is a simple and effective method for constructing difluoromethylene-containing compounds.We synthesized a series of α,α-difluoroestersby the addition reaction of ethyl bromide difluoroacetate to C=C and C=N bond,and expanded the application of ethyl bromodifluoroacetate in organic fluorine chemistry.This paper includes the following three parts: The chapter one:Research progress in the application of difluoromethylene building blocks in organic synthesisThis chapter mainly reviews the application of various difluoromethylene building blocks,such as ethyl bromodifluoroacetate,ethyl iododifluoroacetate,monobromodifluoromethylphosphonate,and monoiododifluoromethylphenyl sulfone,in organic synthesis.The chapter two:Study on the addition reaction of ethyl bromide difluoroacetate with acylhydrazones promoted by tin powderThis chapter explores the addition reaction of ethyl bromide difluoroacetate with in situ formed acylhydrazones promoted by tin powder,and a series of β-N-hydrazinyl-α,α-difluoroesterswereobtained.The method has the advantages of simple operation,low cost and easy availability,mild reaction conditions,wide practicality of the substrates and high yields,and provides a new way for the synthesizing β-N-hydrazinyl-α,α-difluoroesters,and expands the application of ethyl bromide difluoroacetate in organic synthesis.The chapter three:Study on the addition reaction of ethyl bromide difluoroacetate with carbonyl compounds promoted by tin powderThis chapter explores the addition reaction of ethyl bromide difluoroacetate with aldehydes and ketones promoted by tin powder,and synthesizes a series of β-hydroxy-α,α-difluoroesterscompounds.It provides a new way to synthesize β-hydroxy-α,α-difluoroesters compounds,and expands the application of ethyl bromide difluoroacetate in organic synthesis.The method avoids the direct use of toxic organotin reagents and has the advantages of simple operation and mild reaction conditions.