Mechanism Study And Extension Of Rh(?)-Catalyzed Highly Selective Coupling Reactin Of Aryl Sp~2 C-H Bonds With Vinyl Acetate

In recent years,C-H bond activation and functionalization catalyzed by transition metals have developed rapidly.Various methods about C-H bond activation have become continuously expanded.Because of the high catalytic activity,broad reaction substrate scope and tolerance of various reaction conditions,Rh has been a very important part of catalysts in C-H activation.On the other hand,C=C bond is one of the most basic bond in organic compounds.The direct introduction of C=C bonds into organic molecules can achieve a series of convenient synthesis methods.Therefore,Rhodium-catalyzed C-H bond activation and alkenylation have been extensively researched by organic chemists.With the deepening of research,we need to further consider how alkenylation is carried out.The study of alkenylation mechanism can help us improve discovered reactions or develop new reactions.Even some reactions which seem difficult can give reasonable optimization methods by studying from the mechanism.Therefore,in this dissertation,the mechanism of Rhodium-catalyzed N-pyridylindoles or benzamides react with electron-rich olefin vinyl acetate was studied.And Rh(III)-catalyzed oxidative acetylation of acetanilides with more electron-rich olefin N-butyl vinyl ether was designed.This dissertation is divided into five chapters.In the first chapter,based on the theme of this dissertation,the importance of transition metals catalyzed C-H activation and several ways of C-H bond activation are described.Combined with the main content of this dissertation,the research progress of Rh-catalyzed C-H bond activation and alkenylation in recent years is reviewed.Finally,the research purposes of this dissertation are briefly explained.In the second chapter,a series of(E)-1,2-bis(1-(pyridin-2-yl)-1H-indol-2-yl)ethenes were synthesized via a highly region-and stereoselective coupling reaction of pridine directed Rh(?)-catalyzed N-pridylindoles with inexpensive election-rich vinyl acetate.And we studied the reaction mechanism with emphasis.Cyclic metallation complex 2-4 and olefin insertion complex 2-5 were synthesized by stoichiometric reaction,and confirmed to be intermediates for catalytic reactions.It was also confirmed by comparison experiments that the reaction went through the vinylation process of N-pyridylindoles.In the third chapter,the mechanism of oxo-directed Rh(?)-catalyzed coupling reaction between benzamides and vinyl acetate was studied.The first stable oxygen-directed olefin inserting intermediate was synthesized by stoichiometric reaction and proved that it can efficiently catalyze the coupling reaction under standard conditions.It was confirmed by deuteration experiments that the C-H activation process in this reaction was reversible.But the olefin insertion process was very rapid,making the C-H activation process no longer reversible.The reactivity of benzamide and alkene was studied by control experiments.In the fourth chapter,based on the previous mechanistic studies,Rh(III)-catalyzed coupling reaction of acetanilides and N-butyl vinyl ether,which is more electron-rich than vinyl acetate,was developed,and a series of ortho-acetylation productions were obtained efficiently.Among them,the acetylation products were obtained in good yield when the aryl group has a strong electron donating group.In the last chapter,it was summarized the research contents of this dissertation.