Studies Toward Direct Functionalization Of Aromatic Rings

Due to aromatic rings‘ great impression in drugs' discovery and biological science,how to construct aromatic rings directly and effectively is one of the hot point of mordern chemistry.In this paper,we introducted several different direct aromatic C-H functionalization developed by ourselves in the past years.These new chemistries include: direct aromatic halogenation,direct aromatic arylation and direct aromatic lithiation.In Chapter I,we talked about the researches toward direct aromatic C-H functionalization in the recent years.Recording to the different types of chemical bonds formation,we divided these reactions into C-C bonds formation and C-X bonds formation.In Chapter II,we introduced imidazolium salt catalyzed para-selective halogenation of electron-rich arenes.A highly para-selective halogenation of arenes bearing coordinating groups in the presence of a dimidazolium salt as a catalyst was reported.A series of electron-rich p-haloarenes were prepared in good yields and excellent selectivities.We also propose a plausible mechanism for the catalytic reaction.In Chapter III,we introduced photoredox-catalyzed direct C-H arylation of isoquinoline with aryldiazonium salts.A mild and efficient photoredox-catalyzed direct C-H arylation of isoquinoline core strategy was reported.We applied the new strategy in the total syntheses of menisporphine and daurioxoisoporphine CIn Chapter IV,we introduced preparation of a new type of dilithium synthon,primary mechanism of the forming process and the application in hetercycles' syntheses.In Chapter V,we look ahead of the aromatic cycles direct C-H functionalization,and propose the future plan based on our current results.