Transition Metal Catalyzed Allylation And Synthesis Of Indolizines

Transition metal-catalyzed allylation provides an efficient and economical approach to the construction of C-C and C-hetero bonds in organic synthesis,which has been widely applied in the field of building complexed natural products and pharmaceuticals.As an important molecular structure in the development of various small molecule drugs,indolizines exist in a variety of natural products and synthetic drugs with strong biological activity.In addition,indolizine derivatives are the core frameworks of many fluorescent materials,exhibiting excellent fluorescence.Therefore,we were drawn to the researches of transition metal-catalyzed allylation and synthesis of indolizines.Two aspects were studied in this paper.One is the palladium-catalyzed allylation of cyclopropyl acetylene with indoles.The other is the intermolecular cyclization reaction of gem-difluoroalkenes and 2-(pyridin-2-yl)acetate under the catalysis of Cu I.A series of 1,3-dienes compounds with a quaternary stereocenter at C-3 position of oxindoles were synthesized by allylation of phenylcyclopropylenes with oxindoles with the catalysis of palladium and phosphine ligands without using any oxidants,which afforded the desired products in good yields with high regio-and stereoselectivities.In addition,by the control experiment we studied the reaction mechanism and explored the possibility of asymmetric catalysis via chiral ligands.There were 34 compunds obtained in this research.Disubsititued indolizine derivatives were obtained by Cu-catalyzed cyclization of gem-difluoroalkenes and 2-(pyridin-2-yl)acetate via the cleavage of C-F bond.This method exhibited high functional group compatibility,and afforded the indolizines in high yields.In the experiment,23 indolizine derivatives were obtained.