Selective Phosphinylation Of (Hetero) Aromatic C-H Bond And Its Dehydrogenation Heck Reaction With Electron-Rich Alkenes

Although the selective activation and transformation of C-H bond is extremely challenging in organic synthesis,it is an important mean of efficient,green and rapid construction of various organic molecular skeletons,and one of the hot research fields in organic synthetic chemistry.From the perspective of the development of new reagents and new reaction models,two types of C-H bond direct functionalization have carried on detailed research in this thesis,including two main aspects:1)AgN03 or K2S2O8-promoted direct phosphorylation of N-heterocyclic C-H bond,which provides a convenient and efficient route access to a series of promising precursors of hemilabile P,N-bidentate ligands;2)by regulating the steric and electronic effects of X-Cp in[(X-Cp)Rh(Ⅲ)]complexes,efficient and selective dehydrogenative Heck coupling reactions of electron-rich olefins have been realized.This dissertation consists of the following five chapters.In chapter 1,the advantages and challenges of C-H bond direct functionalization are introduced.Specifically,the approaches of C-H bond activation and transformation are summarized,the applications of organic phosphine compounds and the research progress on the synthesis of organic phosphine compounds through C-H bond functionalization are described,and the applications of trivalent rhodium complex[Cp*Rh(Ⅲ)]in dehydrogenative Heck coupling reaction are also briefly summarized.Finally,the main research purposes of this dissertation are briefly presented.In chapter 2,AgNO3 or K2S2O8-promoted direct phosphorylation of N-heterocyclic C-H bond has been developed.Using AgNO3 as oxidant,compounds 3 can be constructed by direct phosphorylation of benzothiazoles and thiazoles;while using K2S2O8 as oxidant,not only compounds 3 can be constructed by direct phosphorylation of benzothiazoles and thiazoles,but also compounds 5 can be synthesised by direct phosphorylation of benzothiophene,2-methylthiophene and benzofuran.Also,compound 3aa can be reduced,affording a novel hemilabile P,N-ligand 7.Ligand 7 can react with[Ru(cymene)Cl2]2,led to the formation of a neutral P-coordinated ruthenium(Ⅱ)complex 8 or a novel cationic ruthenium(Ⅱ)complex 9 containing hemilabile P,N-ligand.In chapter 3,an alkenylation has been developed with cationic rhodium complex[Cp*Rh(Ⅲ)](SbF6)2 as catalyst,which realizes a high efficient dehydrogenative Heck coupling reaction of aryl C-H with electron-rich vinyl acetate.A series of indole derivatives can be prepared following a simple hydrolysis/cyclization process of coupling products.Also,indole derivatives can be synthesized by one-pot reactionIn chapter 4,a simple and facile method for the synthesis of electron-deficient[(X-Cp)RhI2]2/n complexes has been developed,and the studies on dehydrogenative arylation of electron-rich olefins(including vinyl acetates,N-vinyl amide,and vinyl ethers)with electron-deficient[(X-Cp)RhI2]2/n complexes as Rh catalyst precursors are also carried on.This arylation of electron-rich olefins provides a facile and high efficient route toward various styryl acetates,N-acylindoles and aryl methyl ketones.Futhermore,mechanism studies have also demonstrated that electron-deficient cyclopentadienyl ligands have dual effects on Rh(Ⅲ)-catalyzed dehydrogenative arylation of electron-rich alkenes:not only can facilitate the electrophilic aryl C-H rhodation,but also can lower the reaction barrier of electron-rich olefin insertion into C-Rh bond.In chapter 5,the research achievements of this dissertation are summarized.