Study On The Reaction Of Enol Silyl Ethers Participating In The Construction Of Fluorine-containing Organic Compounds Under Weak Interaction

Due to the small atomic radius,low polarizability and maximum electronegativity of fluorine atoms,the introduction of fluorine-containing groups into organic molecules can often change the chemical or biological properties of parent molecules,which are widely used in drug development,clinical medicine,agricultural chemistry,material science and other fields..Therefore,the introduction of fluorinecontaining functional groups into organic small molecules can significantly improve the metabolic stability,lipophilicity and biological activity of the parent moleculars.As one of many fluorine-containing reagents,difluoroethylene silyl ether(dfsee)is introduced into organic molecules α-Fluoroalkylation is one of the most important reagents for carbonylation.There are two ways for difluorenol silanes to participate in the reaction:(1)Ionic difluoroalkylation of difluorenol silanes with electrophilics;(2)Difluoroethylenol silanes are involved in the free radical type of difluoroalkylation reaction.Among them,the free radical type reaction often needs the participation of transition metals.On the basis of our previous work,this paper hopes to develop a metal free method to expand the type of free radical reaction of difluoroethylenol silicone ether through the strategy of weak interaction induction,and has carried out the following three aspects:Part Ⅰ: Visible light-induced deamination(fluoro)alkylation of(difluoro)enol silyl ethers with Katritzky saltsHantzsch ester,a widely used base or electron-donor compounds,was found to act as a catalyst in the deamination difluoroalkylation of Katritzky salts and difluoroenoxysilane as substrates.In addition,substrate-induced pathways were also observed in the absence of Hantzsch ester involved in the reaction process.The synthetic method was conducted under mild conditions,doesn’t require transition metal catalysis,and has a wide range of substrates.Further studies showed that enol silyl ether could also undergo similar reactions,and a series of products were obtained in medium to good yields γ-Ketone ester,is γ-The synthesis of ketone esters provides a simple method.Part Ⅱ: Visible light-induced decarboxylation difluoroalkylation of difluoroenol silyl ethers with redox-active estersUsing a wide range of carboxylic acids as starting materials,after simple activation,using a base as an electron donor,the decarboxylated difluoroalkylation reaction with difluoroenol silyl ether was induced under the induction of visible light.The method has the characteristics of low cost,simple to operate,does not require additional photocatalysts or metals,and a wide range of substrate sources.Part Ⅲ: Visible light-induced enol silyl ether and ethyl difluoroiodoacetate to construct β-fluoroenoneIn this study,visible light promotes the synthesis of β-fluoroenone through the weak interaction of ethyl iododifluoroacetate with silyl enol ethers via the solvent as electron donor.This protocol is also applicable to the synthesis of α,β-polyfluoroenones.The reaction system features mild reaction conditions,excellent functional group tolerance,and synthetic simplicity with costeffective reaction system.