Research On The Addition Reaction Of Pyridine Compounds With Internal Alkynes Catalyzed By Organo-Rare-Earth Complexes

Pyridine widely exists in various natural products,bioactive molecules and material molecules,and the functionalization of simple pyridines has become an important research topic.Among various conversion reactions of pyridine,catalytic pyridine C-H bond migration can provide the most direct and atom-economical method to obtain pyridine derivatives.For example,alkylated pyridine can be obtained by catalyzing the addition reaction of pyridine C-H bond with unsaturated bond,which has the advantages of simple and easily available raw materials and 100%atom economy.Transition metals（Ru,Rh,Ir,Ni,etc.）can catalyze the conversion process of pyridine alkylation by pre-nitrogen oxidation and nitrogen alkylation of pyridine.At the same time,the pre-transition metal catalysts（Zr,Ln）can directly realize the activation and conversion of pyridine ortho C-H without pre-functionalization engineering of pyridine nitrogen.This process is more economical in steps and in line with the concept of green chemistry.Based on the extensive generalization of the catalytic alkenylation of aromatic hydrocarbons,heteroaromatic hydrocarbons with alkynes,this thesis combines our research group’s research on rare earth catalysis of pyridine ortho-C（sp²）-H with monoolefins andα,ω-diolefins.In the research work on the chemical reaction,the organic rare earth catalyzed alkenylation of pyridine ortho-C（sp²）-H and internal alkyne was systematically explored,and this catalytic process was realized for the first time.The main findings of the study are as follows:（1）Mono（phosphinoamide）rare-earth complexe（η²-N-P^R）Ln（CH₂C₆H₄NMe₂-o）₂（N-P^R-Ln）（Ln=Sc,Y,Lu;R=Ph,Cy,iPr）were synthesized,and their structures were determined by ¹H,¹³C,³¹P NMR and single crystal diffraction methods representation.（2）The N-P^iPr-Sc/B（C₆F₅）₃-catalyzed addition reaction system for the ortho-C（sp²）-H bond of internal alkynes with pyridine compounds was constructed,The applicability of the catalytic system to the substituent groups of pyridine substrates was investigated using 3-hexyne as the substrate,using 2-methylpyridine as the substrate to investigate the applicability of the catalytic system to the substitution group of the internal alkyne substrate,a series of addition products of pyridine compound ortho-C（sp²）-H bond with alkyne were obtained,and the yield is as high as 98%.（3）The fate of the vicinal protons of pyridine compounds was investigated by deuterium labeling experiments,and the details of the reaction were discussed by density functional theory（DFT）calculations,and possible reaction paths were proposed.