The Research Of Radical Intermediate C-H Bond Alkynylation And Allylation Reactions

In organic compounds,C(sp3)-H bond is a common chemical bond.Compared with other chemical bonds,the C(sp3)-H bond is very stable because of its bond dissociation energy(BDE)is about 100 kcal/mol;In addition,organic compounds usually contain multiple C(sp3)-H bonds with similar properties,which makes it very challenging for the selective functionalization of specific C(sp3)-H bond.In recent years,with the development of free radical chemistry,the activation of C(sp3)-H bond by free radical chemistry has become an efficient strategy for chemists.For example,The oxidant acts as a hydrogen abstract reagent or O/N radical mediated hydrogen atom transfer(HAT)are the strategies to realize the activation of C(sp3)-H bond.My work during my postgraduate student is mainly to oxidize alcohol to generate alkoxyl radical by oxidant to realize the alkynylation and allylation reaction of C(sp3)-H bond at specific position after HAT;to realize the alkynylation and allylation of C-H bond by using oxidant to grab hydrogen.This dissertation is divided into the following two parts:The first part is about the alkoxyl radical was generated by the reaction of[Bis(trifluoroacetoxy)iodo]benzene(PIFA)with alcohol under visible light irradiation,and then the alkynylation and allylation reaction of C(sp3)-H bond of remote specific site is realized after 1,5-hydrogen atom transfer.This reaction has high regioselectivity.good functional group tolerance,simple reaction operation,without protected by the inert gas or pre-functionalization of alcohol.It has important significance for realizing the functionalization of remote C(sp3)-H bond.The second part is about the PIFA generates free radical to grab hydrogen atom under visible light irradiation,to realize the alkynylation and allylation of the C-H bond.This work is mainly focus on the functionalization of C-H bonds of ethers.aldehydes and amides.PIFA,as a good hydrogen closing reagent,can activate the C-H bonds of ether,aldehyde,and amide under the condition of non-transitional metal participation,which can be widely used in the free radical mediated C-H bond functionalization reaction.