Transition Metal Catalyzed Ring-Closing Dearomatization/Hydrocarbyl Migration Reaction Of Alkyne And Pyrrole Derivatives

Polycyclic pyrrole and its derivatives are an important class of heterocyclic compounds.It is widely present in natural products and biologically active molecules,and is also an important part of drug molecules and organic materials.Therefore,the synthesis and properties of polycyclic pyrrole and its derivatives are one of the focuses of research in the fields of materials science and medicinal chemistry.In this paper,a transition metal catalyst is used to achieve a six-membered ring closure reaction between pyrrole and alkyne,which provides a simple method for the synthesis of this class of pyrrole ring compounds.The first part of this paper mainly studies the selective ring-closing reaction of pyrrole and intramolecular alkyne catalyzed by copper.N-o-alkynyl-2,5-disubstituted pyrrole,under copper catalysis,can undergo ring-closure/hydrocarbyl migration tandem reaction with the alkynyl group in the molecule to obtain pyrrolo[1,2-α]quinoline compounds.If 2,5-disubstituted pyrrole is replaced by fully substituted pyrrole(isoindole),due to the migration site of the hydrocarbon group,this kind of substrate undergoes intramolecular ring-closing dearomatization reaction under copper catalysis.Polycyclic isoindoline products with enamine structure.In the second part of this paper,we mainly study the dearomatization of the ring-closing dearomatization reaction between isoindole substituted by N-o-halophenyl and endyne under palladium catalysis,and polycyclic isoindole with enamine structure can also be obtained Porphyrin products.The reaction has good substrate universality and moderate to good yields.The enamine structure of the resulting product can be directly oxidized to an amide,and can also be trapped by the electron-deficient enone,and a [4+2] cycloaddition reaction occurs to obtain the corresponding spiro product.Based on the experimental results,we proposed a possible mechanism for the series Heck reaction.