Study On Construction Of Selenium-containing Heterocycles And Arylselenonitrile Compounds Based On Elemental Selenium As Selenium Source

In recent years,organic selenium-containing compounds have received more and more attention as biologically active molecules due to their unique anti-tumor,antibacterial,anti-proliferative and anti-inflammatory activities.In addition,organic selenium compounds are also widely present in chiral ligands and functional materials.Organic selenium compounds are also important organic synthetic intermediates in the construction of olefins and natural products such as pancratistatin,sphingosine and schweinfurthin B.In view of their important application and value,the development of efficient,highly selective and environmentally friendly methods for constructing selenium-containing compounds has always been the goal of chemists.In the first part,we focus on the efficient methods for the construction of five-and six-membered selenium-containing heterocycles through Ag-catalyzed radical cyclization of arylboronic acids with elemental selenium.Preliminary mechanistic studies have shown that this transformation involves a selenium-centred radical intermediate.In the second part,we develop a green and simple method for the synthesis of aryl selenocyanates via the three-component reaction of aryl boric acid,selenium powder and TMSCN under metal-free and additive-free conditions.Remarkably,TMCSN acts as not only a substrate but also a catalyst.The strategy can also be applied in the synthesis of various selenium-containing heterocycle with catalytic amounts of TMSCN.