Based On Difunctionalization Of Alkynes For The Synthesis Of Heterocyclic Compounds

Heterocyclic compounds are the most important organic compounds and widely used in agricultural sciences,materials sciences,and life sciences.In view of the important value of heterocyclic compounds,it is of great significance to develop more efficient methods access to them.Alkynes are very important industrial raw materials,because they are cheap,easily available and easy to react via electrophilic addition or radical addition,which has attracted extensive attention from organic chemists.In recent years,great progress has been made in the difunctionalization of alkyne,and it has gradually become a hot spot in the field of organic chemistry.This article mainly focused on the reaction of difunctionalization of alkynes via free radicals pathway toward heterocyclic compounds.Related work was carried out as follows:1.A simple and efficient method for the preparation of benzothiophenes through a visible-light-induced tandem cyclization of 2-alkynylanilines with disulfides under transition-metal-free and photocatalyst-free conditions was developed.The reaction generated the corresponding products in good yields with hydrogen peroxide as the oxidant under a nitrogen atmosphere with 3 W blue LED irradiation at room temperature for 15 h.A broad range of alkynes were tolerated in this transformation.2.The reaction of silver acetate-promoted N-propargyl indole and p-toluenesulfinic acid was established to synthesize sulfoneated stilbene derivatives.The reaction uses silver acetate as an oxidant,providing a sulfone-based free radical source with inexpensive and readily available phenylsulfinic acid.The 2-sulfone 9H-pyrrole [1,2-a]anthracene compound was effectively synthesized under the protection of nitrogen with DCE as the reaction solvent.The reaction has good regioselectivity and high substrate broad spectrum.