Study On Palladium-Catalyzed Domino Reaction Of O-Haloaryl Alkenes

An important propose of organic synthesis is the generation of complex and diverse molecular scaffolds from readily available feedstocks in a minimum number of steps.A widely used strategy to address efficiency in organic synthesis is the utility of domino reactions,which allow the sequential construction of various chemical bonds in a single synthetic operation.Consequently,domino reactions have attracted considerable attention in recent years due to its simple elegance and high economy.Among them,transition-metal-catalyzed domino reactions represent a powerful approach for the expeditious synthesis of highly substituted frameworks with various terminating reagents.O-haloaryl alkenes derivatives show great potential in the field of the construction of heterocyclic molecules,which were widely used as synthetic units in the palladium-catalyzed domino Heck reaction.Therefore,it is of great importance for the synthesis of drug and natural product to develop Pd-catalyzed domino Heck reaction of o-haloaryl alkenes.In addition,internal alkyne molecules have received considerable attention in the field of organic synthesis due to its ability to provide two highly reactive sites.Thus,a palladium-catalyzed domino Heck reaction for the formation of a series of polycyclic structures from o-haloaryl alkynes and internal alkylene is successfully described in this paper.The research in this paper includes the following:1.A novel and efficient Pd-catalyzed cascade aryl-furanylation of alkenes reaction from N-(2-iodophenyl)-N-methylmethacrylamide and o-alkynyl phenols has been developed.This protocol provides a series of benzofuran-containing 3,3-disubstituted oxindoles.Possible pathways for this method were also validated and proposed.2.A Pd-catalyzed domino Heck reaction for the construction of bisheterocyclic methane skeletons bearing all-carbon quaternary centers from o-iodophenylsubstituted allyl ethers and o-alkynyl phenols has been described.A gram-scale experiment was successfully carried out and the product performs the transformation of functional group.3.A series of spiroindolines containing two non-adjacent all-carbon quaternary centers were successfully formed via a palladium-catalyzed Heck cyclization reaction/dearomatization of indoles from N-(o-iodophenyl)acrylamide and alkynylcontaining biaryl indoles.In addition,the products could be converted to benzo[c]carbazole skeletons through ring expansion reactions in the presence of Br?nsted acid.4.A simple and efficient palladium-catalyzed C-H functionalization of indolecontaining alkene-tethered aryl halides from o-haloaryl alkenes and phenyl propargylates has been developed.This reaction furnished the construction of a series of indole alkaloid skeletons.These works have enriched the application of o-haloaryl alkenes in the field of palladium-catalyzed domino Heck reactions.Furthermore,these strategies successfully provide new ideas for the design and experiment of such reactions subsequently.