Studies On Palladium-Catalyzed Highly Selective C-H Bond Nitration

After decades of development,the strategy of transition metal-catalyzed carbon-hydrogen bond activatio n has become an important means to efficiently build new carbon-carbon and carbon-hetero bonds.Compared with traditional transition metal-catalyzed coupling reaction,the direct C-H bond functionalization has great advantages in terms of atom economy,regioselectivity,chemoselectivity and substrate universality and so on.So far,the types of d irect C-H bond functionalized reaction have been very rich.Recently,more and more researches have focused on improving reactivity and selectivity,and controlling the selectivity of reactions by directing groups is becoming a new growthpoint.This paper focuses on the selectivity problem of traditional nitration reaction.We developed a strategy of"transition metal-catalyzed removable directing group-assisted C-H bond nitration",and achieved several ortho-nitrations of certain functional groups(including ketones,aldehydes,phenols)and even alkyl C-H bonds.With our further investigation in this field,we also explored a multi-fold functionalization of carbon-carbon multiple bonds to simultaneously construct five new bonds in one-step process.In first chapter,firstly,we briefly introduced the advantages of direct C-H bond activation and the function of directing groups in the direct activation of C-H bond.Then we reviewed the different types of removable&modifiable directing groups.Finally we discussed the background of this research work.In the second chapter,we briefly described the research status of nitration reaction.Then we investigated the palladium-catalyzed ortho-nitration of C-H bonds and further regiospecific synthesis of o-nitroaryl aldehydes or ketones by using O-methyloxime as a removable directing group.This reaction can serve as a general method for the synthesis of o-nitroaryl ketones or aldehydes with different substituents.In the third chapter,we investigated the palladium-catalyzed ortho-nitration of C-Hbonds by using electron-donating 2-pyridinyloxy as a removable directing group,which can serve as a general method for the synthesis of o-nitro phenols by further removal of the 2-pyridinyloxy group.In the fourth chapter,firstly,we briefly reviewed the research status of directing group-assisted sp~3 C-H bond activation.Then we investigated the palladium-catalyzed sp3 C-H bond nitriation by using by quinoline as a directing group.The reaction has advantages of good regioselectivity and broad scope of substrates.The resulting nitrated products can be further reduced to(1,2,3,4-tetrahydroquinolin-8-yl)methanamine.In the fifth chapter,firstly,we briefly reviewed the research status of the mono-,di-,and multifunctionalization of carbon-carbon multiple bonds.Then we investigated the silver-promoted multifunctionalization of terminal alkyne,which provided an efficient method for construction of five new bonds in one-step process.In the sixth chapter,we made a summary of the total contents of this thesis,outlined the future trend of carbon-hydrogen bond activation,and discussed the importance of further study of the above mentioned multifunctioned reaction of carbon-carbon multiple bonds.