Palladium-catalyzed Ortho-C-H Bond Activation Of Benzoic Acids And Meta-C-H Bond Activation Of Anilines

The transition metal catalyzed inert C-H bond functionalization is one of the research frontier fields of organic chemistry.The reaction is atom-economical and it can improve the efficiency of target molecule synthesis,conforming to the concept of green,economic,and efficient synthetic chemistry and meeting the requirements of sustainable development.Thus the reaction has an important application prospect in natural product,medicine,and organic functional material preparations.Unlike the traditional organic synthesis method,inert C-H bond activation does not require prefunctionalization of the raw materials,and can directly transform the pervasive non-activated C-H bond in organic molecules into C-C,C-N,C-O bond and other functional groups,which can lower synthetic steps,reduce waste emissions,greatly improve the efficiency of target molecule synthesis and save the resources and energy.In addition,the research on transition metal catalyzed C-H bond activation can improve the understanding of a chemical bond and the interaction mechanism between metal and a chemical bond,thus effectively expanding the application fields of transition metal catalysis.Therefore,the study on new and efficient C-H bond activation reaction is of great significance.This thesis mainly includes two research topics of palladium???-catalyzed ortho-trifluoroethoxylation of benzoic acid derivatives and meta-C-H olefination and acetoxylation of aniline derivatives.1.A broad range of benzoic acid derivatives were ortho-trifluoroethoxylated with palladium???acetate as the catalyst under the mild conditions,which gave the corresponding products in a moderate to good yields.After ortho-trifluoro-ethoxylation,the first meta-C-H trifluoroethoxylation was achieved by introducing a meta-directing group,which was used for the synthesis of core segment of drug molecule Flecainide.2.We have developed a novel meta-C-H activation directing group for aniline derivatives by facile incorporation of CO₂ into the carbamate under mild basic conditions for the first time.A broad range of aniline derivatives were efficiently olefinated at the meta-positions with good functional group tolerance.meta-C-H acetoxylation was also proved to be viable.Moreover,the carbamate directing group could be easily cleaved under basic conditions and the meta-selectivity was generally excellent for the aniline derivatives.All of these features are beneficial for the potential application of this method in late-stage C-H functionalizations of complex molecules.