Asymmetric Organocatalytic Michael/Cyclization Reaction:To Construct The Indole-fused Thiopyran Compounds

As an important structural skeleton,Indole and its derivatives are favored by organic chemists,medicinal chemists and biochemists,it is a very active area of Heterocyclic Chemistry.particularly due to their natural occurrence and pharmacological activities.A large number of indole derivatives are at the fore as pharmacologically active lead compounds for drug development.Indole derivatives also occur widely in many natural products such as those from plants,fungi and marine organisms.There are several thousands indole derivatives known and many of these have important pharmacological activity.In many cases,indole compounds can be synthesized by organic catalytic manner,and the yield and the ee%of products can reach very high levels.Also,these compounds have attracted more and more concern.It is important to bear in mind,however,that many organocatalysts(cf.amino acids,phosphoric acids)act through both covalent and noncovalent interactions and/or display a dual acid/base character("bifunctional catalysts").The construction of heterocyclic compounds by chiral bifunctional imine thiourea catalyst can be completed in a very effective way.In recent years,We have developed a new bifunctional amine thiourea catalyst based on rosin,which we used to construct the bioactive indole-fused thiopyran and its derivatives through asymmetric michael/cyclization reaction.The catalyst and the substrate used are easily available and the reaction conditions are mild.The reactions are carried out in a very short time.The indole-fused thiopyran we obtained has a variety of potential biological activity.Besides,it is very important skeleton in many pharmaceutical and biologically active compounds,which has been found as a phytoalexin.Nowadays,its importance has been more and more concerned.