The Novel Application Of Ethyl Bromodifluoroacetate In C-H Activation

Transition metal catalyzed functionalization of inert hydrocarbon bonds is the most efficient and direct way to achieve carbon carbon and carbon heterozygous bonds.It has the advantages of green,atomic economy and so on,which attracts the attention of the majority of scientific workers.In recent ten years,the functionalization of hydrocarbon bonds has been widely used in the synthesis of natural products,the construction of drug molecules,and the synthesis of materials,and many excellent results have been achieved.This paper mainly studies the application of ethyl bromodifluoroacetate,a cheap and easily available fluoroalkylation reagent,in the functionalization reaction of carbon-hydrogen bonds.This paper is divided into the following parts:The first part:systematically summarized the development and application of difluoroalkylation,and summarized the application of ethyl bromodifluoroacetate as a fluoroalkylation reagent in the introduction of fluorine-containing functional groups;in addition,summarized the development of hydrocarbon bond ester reaction.The second part:the synthesis of monoethyl aromatic acid and its derivatives was studied.It was found for the first time that ethyl bromodifluoroacetate can be used as a new carbonyl source,and palladium catalyzed ortho direct esterification of benzoic acid can be realized.The new type of hydrocarbon bond esterification not only has good universality of the substrate,but also does not need additional auxiliary groups.The preliminary mechanism experiment shows that the reaction is carried out by free radical way.In the third part,ruthenium catalyzed esterification of phenol with m-difluoroacetate was studied.It was found that ethyl difluoroacetate functional group could be selectively introduced into the position of phenol by using 2-chloro-5-methylpyrimidine as the leading group precursor,through the regulation of AgNTf2,ligand and catalyst[Ru(p-cymene)Cl2]2.The strategy has the characteristics of good substrate applicability and yield,and provides an efficient way for the synthesis of m-substituted phenol.