Aliphatic Aldehydes Involved Oxidation Decarbonylation Free Radical Cascade Reactions

In recent years,the strategy of constructing C-C bond through direct C-H bond activation has been developed into a boom in modern organic synthesis;Among them,the use of free radical cascade reaction to construct a variety of C-C bonds has been used to synthesize many bioactive molecules,which becomed a common,efficient and convenient way.In this context,the alkylation of acrylamides has been achieved to produce functionalized indolone compounds.Compared with the traditional transition metal catalyzed alkylation of acrylamides with halogenated alkanes,free radical cascade reactions avoided the need for the pre-functionalization of the substrates,additional ligands nor alkaloids and diminished byproducts at the same time.However,they were limited to the use of structurally symmetrical cycloalkanes or benzyl C(sp3)-H bonds of arenes to improve regio selectivity.To this end,we hoped to develop a more convenient and effective method,with simple and readily available starting materials as alkyl radicals precusors to realize the cascade cyclization reaction of acrylamides.This dissertation focused on the followings: first,summarizing the progress on free radical cascade reactions of acrylamides and the development of aldehyde oxidative decarbonylative reactions;then,DTBP was used as free radical initiator and oxidant to study the decarbonylative cascade reaction of aliphatic aldehydes with acrylamides,and the substituted indole-2-one products were obtained.The reaction did not require metal catalyst and any other additives,the substrates scope was wide and good regioselectivity and high yields was obtained.No rearrangement of alkyl radicals occured during the reaction.We have also proposed a non-chain free radical addition ringing reaction mechanism.Finally,based on the previous resulst,we tried to apply the decarbonylation of aldehydes to other cascade reactions,so oxidative decarbonylative radical cyclization of phenylpropynyl ketone and phenylpropyne was tried to build other types of carbon-carbon bonds and cyclic compounds.