The Study Of Steering Synthesis Based On The Heck Reaction Assisted By The Weak Coordination Of Neighboring Groups

In the modern organic synthesis,the strategy of using assisting group has been extensively used in many organic reactions.At present,there are three types of research based on this strategy:(1)Exploiting the directing function of the assisting groups,to realize the regioselective functionalization and then to develop new-type of reaction.(2)Exploiting the weak interaction of the assisting groups,to ameliorate the intrinsic reaction and then to improve the efficiency of the original reaction.(3)Changing the stability and reactivity of the reactive intermediate by installing the assisting groups,and then to bias the reaction away from the original reaction.Among them,the first and second types are widely reported and applied,but the third type of research is mainly limited to the assistance of the strong-coordinated groups,which bring about a large research gap.The Heck reaction is a kind of very important cross coupling reaction,which won the Nobel Prize in chemistry 2010.Up to this day,researches on the Heck reaction focus on the in-situ capture of the Heck type intermediate,by exploiting new strategies and functionalized reagents,and thereby to restrain theβ-hydrogen elimination,biasing the intrinsic Heck reaction away and finally develop the novel Heck reaction.In this thesis,we use phenolic hydroxyl as the weakly coordinated control center,which is also tethered to olefin as the substrate,to be mixed with another aryl halide under palladium catalysis,based on the combination of several elementary reactions such as coordination,decoordination,C-H activation,etc,successfully developed several novel Heck reactions.This study not only provides a strategic expansion of the Heck reaction,but also enriches the cascade reaction modes of the phenolic compounds.The main contents are as follows:In chapter 1,we first introduced the significance of group assisted strategy in the development of modern organic synthesis,and then summarized the related progress of the reactions for phenolic hydroxyl as the assisting group in recent years.Finally,we discussed the development of the Heck reaction and proposed our research mentality of this thesis.In chapter 2,on the basis of palladium-catalyzed Heck coupling,exploiting the strategy that phenolic hydroxyl as the weakly coordinated assisting group.We successfully synthesized a series of polysubstituted phenanthrenes by using aryl halides as substrates,through integrated the processes of Heck coupling,coordination,C-H activation and dehydrogenation,etc.In chapter 3,on the basis of the previous chapter and palladium-catalyzed Heck coupling,exploiting the strategy that phenolic hydroxyl as the weakly coordinated assisting group.We successfully synthesized a series of novel silicon-containing organic compounds by using aryl halides and hexamethyldisilane as substrates,through integrated the processes of Heck coupling,coordination,C-H activation and protodepalladation,etc.In chapter 4,on the basis of the previous chapter and palladium-catalyzed Heck coupling,expoiting the strategy that phenolic hydroxyl as the weakly coordinated assisting group.We successfully synthesized a series of novel boron-containing organic compounds by using aryl halides and bis(pinacolato)diboron as substrates,through integrated the processes of Heck coupling,coordination,C-H activation and transmetallation,etc.In chapter 5,on the basis of the previous chapter and palladium-catalyzed Heck coupling,exploiting the strategy that phenolic hydroxyl as the weakly coordinated assisting group.We first realized the direct annulation of 2-Iodobiphenyl with non-terminal alkene under the palladium catalyst,which further expanded the application universality of this strategy.In chapter 6,on the basis of the exploration of key experimental conditions,we developed a highly selective cleavage of alkynoates as well as different cyclization modes with naphthol under palladium catalysis.Through integrated the processes of nucleophilic substitution,1,3-palladium shift,migratory insertion andprotodepalladation to constructed dibenzo[c,h]xanthene andbenzo[h]coumarin derivatives.In chapter 7,the summary of this thesis and the outlook of future work for the strategy of weakly coordinated groups dominated reactive intermediate were given.