Palladium/Silver Co-Catalyzed Divergent Dimerization Of 2H-Azirines For Regioselective Synthesis Of Tetrasubstituted Pyrroles And Pyrimidines

Both pyrroles and pyrimidines are extremely privileged nitrogen-containing heterocycles,which are core structures of many natural products and biologically active molecules.They have found broad applications as pharmaceuticals,flavors,agrochemicals,and functional materials.Accordingly,many scientists have shown remarkable interest concerning the methods for constructing these skeletons.2H-azirines are highly strained three-membered heterocyclic compounds which have served as synthetically useful building blocks in organic synthesis because of their unique reactivity.In the past decades,2H-azirines have been exploited to react with various compounds to construct a plethora of five-membered/six-membered N-heterocyles and fused N-heterocyles.By contrast,methods for the synthesis of N-heterocycles from 2H-azirines via dimerization process are still underdeveloped.Herein,this paper mainly discusses the divergent synthesis of five-membered heterocyclic compounds and six-membered heterocyclic compounds through palladium-silver co-catalysis,using 2H-azirines as starting raw material,which are mainly described in the following two parts:First,we described the synthesis of tetrasubstituted pyrrole compounds with moderate to good yield by palladium-silver co-catalyzed dimerization of 2H-azirines under the condition of lithium carbonate.This method is simple to operate and has good functional group tolerance.In the second part,we introduced the dimerization of 2H-azirines catalyzed by palladium-silver and the formation of tetrasubstituted pyrimidine compounds by regioselective annulation,which provides a new direction for the efficient synthesis of pyrimidines.