Study On Cyclopropane Reaction Of Difluoroacetaldehyde N-sulfonylhydrazone (DFHZ) With Olefins Catalyzed By Iron (Ⅲ)

The derivatization of organic compounds and fluorine-containing groups often affects their physicochemical and biological properties.In drugs,fluorine-containing groups are usually introduced into the organic chemical framework to enhance their biological activities.Fluoroalkyl diazo is a highly functional fluoroalkyl reagent with strong reactivity.However,because of its well-known toxicity and explosiveness,it can not adapt well to large dose reaction,which limits its application in industrial production.In recent years,there have been many studies on the reaction of fluoroalkyl diazo,but most of them adopt different experimental methods to reduce the risk of the experiment.Sulfonylhydrazone,as the precursor of diazo,can decompose to diazo through the catalysis of alkali at low temperature.This strategy can be used as a safer way to generate diazo and participate in the reaction.In this study,three kinds of difluoroacetic aldehyde n-sulfonylhydrazone(DFHZ)with different sulfonyl groups were prepared from the commercial ethyl difluoroacetate by LiAlH4 continuous reduction and sulfonylhydrazine condensation,and the corresponding DFHZ-TFs,DFHZ-Ns and DFHZ-TS were provided in excellent yields.In addition,difluoroacetaldehyde n-sulfonylhydrazone(DFHZ),the precursor of difluoromethyldiazo,was used to react with olefins under the catalysis of transition metal iron(Ⅲ),and difluoroalkyl cyclopropanization was realized efficiently,green and selectively.